I just started playing these ones recently and have done well. Particularly the rebuy ones because there are people who play really bad.
Play big
hands with big pots and set mine otherwise. Almost all of my really large wins have been with AA/KK or sets. With the 'rush' style of play your going from table to table so unless they have notes on you they're not going to know how your playing otherwise. The first time I played the 2.20 one...i cashed for 85 and i never rebuyed.
I think they are good ROI