Well all i can says is that these two stites are good for me, I was with crestock and they never except pictures and when they do (6) no one seams to be selling. Their people that check the pictures and the admin are very rude.
If you check out their forum, I found it to very very negative from all that write on it.
So keep up the good work shutterstock and istock, you making me happy at the moment.