I've tried a few sites (with Dolphin HD and Skyfire).
The Fox shows (tried Family Guy, American Dad, and Cleveland Show) and they all are jerky and the audio is off.
CNET seems to be a bit better but video is a bit jerky (not too bad though).
CBS doesn't look bad, although the site was a pain to navigate with all the flash on. Tried the show Flashpoint and it seemed to be ok, but would frequently slow down to like 1 or 2 frames per second.
Justin TV seems pretty choppy.
Honestly, kindof disappointed. Was hoping it would be better than it is. Not sure if it's the browser, the flash support, or the phone....