Yesterday I sold some old gift cards to Cardpool. After reading the negative reviews on this site, as well as the fact that their process requires you to just blindly trust them, I was incredibly leery.
They came through though. I uploaded the codes in the afternoon, received a phone call a couple hours later where I verified some info, and got my amazon gift card for the full amount emailed to me before I went to bed.
It couldn't have been an easier transaction.
I cant speak for what happened to other people, but for me it was excellent.