I don't know if this has been done before but what do you like and hate about each of sites you submit to? And any tips you'd like to share.

Here's mine:

Shutterstock:
Likes - The amount of sales and the recent pay rise, the forum, fast reviews and the community of submitters, easy upload process.
Hates - I'd like the ability for a buyer to search my portfolio.
Tips - Keep uploading on a regular basis ( like you didn't know)

iStock:
Likes - Again the sales and to be able to get payouts when you want, I love the statistics facility and the tiered commision structure.
Hates - The 'kiss ass' exclusive side of things, their marketing strategy, the way the forum is policed, disambiguation and of course the upload limit.
Tips - Bare minimum of keywords till it's accepted, oh and don't criticise them in the forum you get told off!

Dreamstime:
Likes - Regular sales and good commision, good upload process and the ability to use categories from a previous image.
Hates - None really, wish they'd accept a broader range of images though.
Tips - I don't know of any but would like some.

Fotolia:
Likes - Struggling on this one, sales aren't bad though and you get to see who bought.
Hates - Where to start, the search engine, worst upload process of every site, ridiculous categories, their keyword system, sloowwww site to work on. And you can't edit your keywords on accepted images.
Tips - Drink plenty of coffee before uploading you'll be there a while

Stockexpert:
Likes - For me good sales, easy uploads and no categories unless you want to, the forum isn't bad, helpful and quick admin support, the fastest reviews of all the sites I submit too. If you get a rejection they give you what I think is a genuine and understandable reason.
Hates - I don't have any, they don't accept all the type of images I submit but in a way I like that, shows their focused on their market.
Tips - If you don't agree with a rejection send them an email they're pretty good I've found.

LuckyOliver:
Likes - Friendly and helpful people, openess, easy upload process and the best reviewers of all :-)
Hates - No more graphs and statistics please, do some marketing and get some sales.
Tips - I haven't found any that work yet.

BigStockPhoto:
Likes - They take nearly everything, reasonable upload process.
Hates - I don't sell much there, but it's getting better.
Tips - I need some.

Featurepics:
Likes - Nice site, very friendly and helpful people, you price your own work and pick your own license, they take editorial.
Hates - I don't sell much there and can't work out why, I can't get Filezilla to remember the FTP settings, I'd like to be able to set a pricing level for different types of images.
Tips - I really need some here.

123RF:
Likes - Yes I like it here and get quite good sales, easy upload and no categories, quick admin support, automatic payouts.
Hates - The forum needs some work on it, I can't work out when and who posted what.
Tips - I've done the interview thing but haven't been featured yet so who knows.

Crestock:
Likes - Hahahahahahaha, the logo is quite nice
Hates - Everything
Tips - IMO Don't bother

and I know it's not Microstock but as it's mentioned here quite a lot,

Alamy:
Likes - Sales and the amount you get, marketing coverage, easy to manage your images, plain and simple no fuss site. Being able to sell under as many psuedonyms as you want.
Hates - Takes a while for the cheques to come, having to send images by post (my last two never arrived), slooowww review process.
Tips - Send your CD's by recorded delivery :-) Read up about the new AlamySearch.

Well that's it for me, hope you take the time to add yours.

__________________
Richard

Shutterstock:
Likes - Sales, great help on forum, unpoliced forum, fast reviews
Hates - Not terribly happy with the reviews but its a two way street when it comes to getting photos accepted

iStock:
Likes - Sales are as good as SS on half the portfolio, statistics are great, great feedback on rejected photos
Hates - Disambiguation isn't the greatest, could use a better uploading tool

Dreamstime:
Likes - Upload process
Hates - Narrow range of images accepted, ridiculous rejections, some outrageous rules and changes to the site

Fotolia:
Likes - Decent sales, most EL sales of any site
Hates - Nasty uploading process

Stockexpert:
Likes - Easy uploading, thats about it
Hates - I find the rejections quite inconsistent (for me) since they accept some and reject similar images as stuff they aren't looking for. Sales aren't great. Someone should tell reviewers that "We aren't looking for this type of image" is not a generic rejection

LuckyOliver:
I need $25 to a payout. Its taking forever and I'm kind of getting impatient.

BigStockPhoto:
At max $10 a month in a good month, there's not much here to talk about but I think its a decent site and the low payout is really good.

Featurepics:
No sales, stopped submitting a while back.

123RF:
Will be uploading more since all I have to do is upload through FTP.

Crestock:
Have never actually been to the site

Alamy:
Will be preparing an Alamy submission very very soon. Prospect of RM is much more exciting.

That pretty much says it.

Shutterstock
Likes: Rapid sales, review times, upload process, lifetime referral income, simple categories.
Dislikes: I'm not crazy about having to upload increasingly larger quantities of images to maintain current levels of income. Search engine doesn't fully separate illustrations from photos. Searching for our own photos in the users area is tedious for large portfolios.

iStock
Likes: Controlled vocabulary and disambiguation (even though it's more work on my end), Creative Network, sales, comprehensive stats, various tools developed by the community, Article of the Week, Designer Spotlight.
Dislikes: Constant fiddling with the search algorythm.

Dreamstime
Likes: Categorization system, Ellen's blog, option to have images keyworded for a fee, consistent sales without huge fluctuations.
Dislikes: Six-month commitment on all images, long review times, confusing commission structure, high payout level.

StockXPert
Likes: Folder system for organizing, categorizing after approval, categories that make sense, recent increase in sales rivaling DT, fastest review time of all the sites.
Dislikes: None

BigStock
Likes: Low payout, decent review times, acceptance rate
Dislikes: The site is a bit cumbersome to navigate, questionable partnerships

Fotolia
Likes: Knowing who bought my photos so I can develop a list of "clients"
Dislikes: Don't get me started.

LuckyOliver
Likes: Simple user interface, open communication, comments instead of ratings, funky atmosphere, opportunities to learn and grow, priority on educating designers and artists, and of course the detailed reviews (which is why I became a Bouncer).
Dislikes: None.

123RF
Likes: Easy uploading, increased royalities every month (instead of a yearly raise), staff responsiveness.
Dislikes: Forum is glitchy (I can't even post on it), series photos often rejected for "too many similar," site is cumbersome to navigate.

Canstock
Likes: Auto categorization and keyword suggestions
Dislikes: Lack of sales, site design is too cluttered and appears dated

FeaturePics
Hard to comment, because I don't visit the site very often.
Likes: High commission (although I can't help but wonder if it might work against them, because there isn't a lot of revenue available for marketing), approval of everything I've ever submitted.
Dislikes: Lack of sales

__________________
Photography by Karin Lau | SmugMug Pro Account | Shutterstock | Mostphotos | StockXPert | Dreamstime | iStock | 123RF | BigStock

Thanks for doing this! As a newcomer to the microstock game, this information is very helpful to me.

Shutterstock:
Likes: Great sales, quick pay, excellent forum, fast review time, FTP, easy keywording, many different formats accepted for video clips.
Dislikes: Rejection reasons of late have been peculiar, site navigation could be better.

iStock:
Likes: Good sales, detailed stats, easy pay-out system, accepts wide range of imagery from stills to video clips.
Dislikes: Disambiguation and keywording is a pain, the whole "exclusive" thing, no FTP for images, or nonexclusive videographers, restricted speech on forum, rejection reasons sometimes weird, hard to get a 3D renderings accepted.

Dreamstime:
Likes: Good sales, FTP, easy keywording and categorization, Ellen's idea-loaded blog, nice site navigation, good forum, easy pay process.
Dislikes: Never had a response back from support on any question or issue sent to them, editorial pics require release forms, speculative definition of what is defined as an editorial photo.

Fotolia:
Likes: Decent sales, FTP, excellent acceptance rate of submissions.
Dislikes: Wonky categorization process, for me older images sell far better than newer ones.

Stockxpert:
Likes: Steady sales, FTP, fast review time, easy keywording and categorization.
Dislikes: Unhelpful rejection comments.

LuckyOliver:
Likes: Run by nice, friendly folks, FTP, excellent site interface, easy keywording, nice blog, happy-go-lucky atmosphere.
Dislikes: Almost nonexistent sales.

Shutterstock:
Likes - I make the most money with them. Simple upload. Good forums. They pay promptly every month
Hates - They don't sell enough photos with their per picture site. Would be nice to get more than 30 cents more often. I get the feeling they don't want their downloaders to max out on downloads, as that costs them money. There are less ways for us to display our images than with some sites.

iStock:
Likes - Good sales. Can put photos in lightboxes. The user Blog and creative network can be useful.
Hates - Recently they changed the best match search and my sales went down 40%. Non exclusives only get 20% commission. This is far too low. They sometimes reject for poor keywords then reject for another reason when the keywords are corrected. Sometime the inspectors reject a photo for the wrong reason.
Tip - If you have a lot of photos of a particular theme, make a lightbox. This is one of mine royalty free stock photography community | iStockphoto.com

Dreamstime:
Likes - It took a long time but I am starting to see good sales.
Hates - Sometimes they reject an entire batch of my photos, sometimes they accept every one. There is absolutely no consistency. Some of my best selling photos have been rejected. They reject my photos for bad keywords when there are lots of photos with inappropriate keywords accepted.
Tip - I upload in tiny batches, as one reviewer seems to just reject all of my photos.

Fotolia:
Likes - Reasonable sales. They have more EL's than most sites.
Hates - The site looks old and is very slow. The upload process is about as much fun as hitting your head against a wall.
Tip - the site is sometimes easier to access at the weekends.

Stockexpert:
Likes - Good sales from the first day I uploaded to them. A fresh looking site that is usually fast and makes it easy to find photos. They have the fastest review times, sometimes less than 5 minutes after I have uploaded them. They accept most of my photos and reject other peoples
Hates - Can't think of anything

LuckyOliver:
Likes - A nice modern fresh looking site that has obviously been designed properly. The most straightforward upload process.
Hates - Sales are slow but mine are steady and I don't mind giving them time to improve.

BigStockPhoto:
Likes - I find their site easy to search and their sales are quite good
Hates - Having to think of at least 7 words for the description of each photo is a pain.

Featurepics:
Likes - They accept and sell photos that are rejected by other sites. They pay 70% commission, more than any other site. It is good to choose how much to sell for.
Hates - Very low sales. The site looks poorly designed when compared to Lucky Oliver.

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istock-Shutterstock-Bigstock-Mostphotos-Dreamstime-Stockxpert

Haha...your series of words made out Play Dough are more stockworthy than mine. My entire series was rejected by IS for not being "suitable for stock" about the same time that yours were accepted. :-?

__________________
Photography by Karin Lau | SmugMug Pro Account | Shutterstock | Mostphotos | StockXPert | Dreamstime | iStock | 123RF | BigStock

But they haven't sold, so perhaps your reviewer was right.
They did reject the only one that has sold well on other sites

__________________
istock-Shutterstock-Bigstock-Mostphotos-Dreamstime-Stockxpert

SS Likes: Everything, except:
SS Hates: I want to see more data for people's images, such as dls and view numbers. That would help me see what is selling.

IS Likes: The forums and other info provide the best tutorials and know-how of any stock site.
IS Hates: "We do not find this suitable for stock." IS is the least business-like of all micro sites. They seem to have secret policies and hidden agendas which determine which images they accept and which have nothing to do with selling more images.

SXP Likes: Since they moved their servers, their site is FAST! And I love the submission process and the fast acceptance.

DT and SXP Hates: For each vector, you have to submit a raster version which is stockworthy as a raster; this is awkward or impossible for any vector which only makes sense as a vector.

CS, LO, FO, and BSP Hates: Slow sales. And FO is the slowest and glitchiest of all microstock sites, in my experience.