They have game settings on lowest possible on all games and then they also stream awfully low quality flash videos, just like Youtube 360p.
The mouse lag between you and server while playing shooting games or games which require precise aiming is just awful too. (Maybe I'm picky, but it sure as hell annoyed me.)
I guess Onlive is good for casual or slower paced games.
I just like onlive cause its Streaming games. And if you get the micro system for 100 bucks, its amazingly better! also, i have a terrable PC, with a normal connection, and onlive works awesomly for me. also, i love the free fetures that onlive has, like a 30 minut trial of the full game! The arena, which is were you can instantly watch people play games live! even if you dont own it! and onlives deals, they are awesome! I geuss for a PC Gamer as my self, its good! And btw, they dont stream as low as possible, you just need a really good HD/HQ PC.