My one time dealing with them, I wound up getting ripped off for $150. I tried purchasing a RBS home cart through them, and I went through all of their steps in order to get the game. They charged my card, but I never got a response to any of the e-mails I sent them.
Luckily, I was able to get the charge taken off of my card, so I don't need to fight Super Sellers for a refund. But it will prevent me from ever doing business from them again. Other people have been lucky, so I guess it all depends. They've done right by many other people on this list, so I guess it's up to you to judge whether or not you want to deal with them.