I love my Super Fat Cat!
I'm a big guy, 6'2' and 280 lbs and my Super Fat Cat easily handles my size. It's very stable and handles well on the water. I'm mostly in saltwater and it's very robust. I've bumped into docks and rocks and yet to have a problem.
I read the review from the guy who thinks the valves on seat and back cushions are a problem, but I have no idea what he's on about. The covers on the seat and back valves are just dust covers and don't have anything to do with the valves sealing. Honestly, they're fine.
I'm very happy with my Outcast tube and I've yet to see anything of higher quality out there. If you want the best, get the Super Fat Cat!