To be honest, the bad reviews on this page almost made me stay away from 99designs.com
I decided to go through with a $499 contest anyway & trust their refund policy. I received a lot of nice designs & very good ideas (along with a bunch of bad ones, but you can just delete them with a click). I didn't get anything that I wanted to pay for. So I called them for a refund. It literally took about 30 seconds for them to process my refund. If they had issues with refunds in the past, they seem to be gone now.
I think if I ran a contest for anything other than this current project, I'd probably have a logo I love. If I took my favorite designs & went to the next round to refine them, I might of come up with something great too. I just didn't want to risk it.
I will definitely be back to run some contests for my other projects.