Dreamstime I think is a good one, no exam to get in, decent sales.

I have recently started my journey into stock photograpy with a little 31 photos batch, most of them from 2007 taken with a Nikon D50 with cheap glass. Recently upgraded to Nikon D7100 with a Nikon 70-200 f/2.8 VR II and Sigma 24-70 f/2.8. So hope to bring my quality up a bit.

My first impression:

Shutterstock: Did not get accepted as contributor on first try.
Dreamstime: Slaughtered 27 of 30 photos (removed one myself due to noticing it included brand name).
Fotolia: Only let me upload 13 images due to resolution, witch excluded some of my best pictures. Accepted 7 and and rejected 6
Bigstockphoto: Rejected 26 and accepted 5.
iStockphoto: Rejected 5 and accepted 26. All 5 rejections was due to possible trademarks, just a legal issue.

I was very excited to be accepted as a contributor on iStock, the only stock agency beside SS i was familiar with before starting my journey into stock photography. To get the first image accepted on iStock was a fantastic moment.
To get 26 out of 31 images accepted saved my day and it makes me rethink of I want to go for exclusive or not.

I got a really bad first impression of Dreamstime and Bigstock after being slaughtered for images that iStock and Fotolia accepted.

Waiting for the spring to get out more with my camera to grow my portfolio and hope to get some studio gear for next winter to do more isolated shots