I had a minor issue with CardPool the first time I ordered from them. I received a gift card code that was not valid. They cancelled my order and refunded my money, which showed up back in my PayPal account within about 3 days. Since then, I have not had a single problem with them. In fact, I have frequently received my gift card information BEFORE I receive my confirmation e-mail. I have received my codes within minutes of placing the order and I have not received another "bad" card.
I have used Raise, CardPool and CardCash so far and I've not had any major issues with any of them. I typically check to see who has the biggest discount on the denomination that I am looking for at the time and go with them. I know that CardPool and Raise have lifetime limits on rebates through their affiliate marketing sites (Sunshine Rewards, Swagbucks, and TopCashBack) so I look at CardCash first, but lately, CardPool has had Target cards consistently at 7% off.
Hopefully CardPool will get their act together and improve their customer service. I see people have also had issues with CardCash too so I think it is really hit or miss. As long as they make it right, I am willing to deal with the hassle, especially considering the amount of savings involved.