One guy did reply, and said they are very good. I have only sent Stiffy Cash limited traffic, (mainly because I have WAY TOO MANY SPONSORS!!!)
so I just get a sale here and there, but the conversions are pretty good and they pay on time every time.
I'm not sure if you have already signed up, but of course you are welcome to use my ref code if you like:
Stiffy Cash 
Bruce