It comes with a pre installed flash player. Which i suppose, like the atrix's own, is optimized specifically for the galaxy s.
I have a captivate right now, and it's running 2.2, and whilst it can play 720p youtube videos, they are choppy, so not much use. More than likely however, it will be able to play it more smoothly when a T&t rolls out the gingerbread update for it. If they ever plan to. =.=
If you're on top of the dung heap you're still on the dung. Only difference is you crawled all the way up.