I signed on with Photospin a year and a half ago.  I should have done it sooner.  At the time they were offering $20.00 per image accepted.  I knew this wouldn't last and submitted what I could.  I made a few thousand $ (several years worth of microstock for me).  Then they offered $10, then $5 and then they stopped accepting under that model midway through 2008.  Beware-they also put some of my images on alamy, which I didn't like, but they are so far down in the ranking I don't think anyone will see them; PS did offer a revenue share if one licensed though.

regarding the new model-there is no way I would sign the new contract.  As someone pointed out, they are charging 10% or less what others are.  It sounds like your take would be only 2-3 cents per image downloaded.  I would steer clear.

gsc

I'm new to shutterstock with about 100 accepted images up for just over two weeks (50% acceptance ratio) with about 200 total downloads.
I am very happy with the results.
  After 7-20 downloads per day, I suddenly have none.  Is it normal for sales to drop off so rapidly?

Any regular sellers who can give me an idea of a typical "curve" of download activity (not counting for seasonal ups and downs).   

I understand the need to continually upload bit by bit, but I'd hate to think that I have to upload hundreds every two weeks just to maintain sales.

Thanks