I recently became a contributor at Pockestock Photo by invitation, and now I have 500 images in my portfolio. I had no sales yet, and it looks like is going to follow CanStock with zero downloads every month. The site is very slow, and freezes all the time, probably affecting buyers also. I will wait 6 months before I give up on them.
Overall, Shuterstock is the best miscrostock site for downloads, and earnings. I just wish they had better reviewers, no bugs on the site, and all of us would benefit from it. On a positive side, the review process is way faster, and soon I will reach 5000 downloads.
http://www.shutterstock.com/pic.mhtml?id=115427305