I've never used them but they have a much higher cash out threshold ($100!!) and I don't know if they pay. I love SR and know they pay and have great CS so I'm sticking with them and my other little programs. For some reason I just think when they offer such high payouts (much higher than other sites) then it might be too good to be true.
I haven't great things either...I think I read fifteen thousand sites/forums/etc when I first learned about this from Dis (ok maybe not fifteen thousand but it feels like it)
I love SR - you can't trade great customer service for anything!