I know lots of people here have better setups, but yesterday I enjoyed my first game with MLB.tv though AppleTV on my large living room flatscreen.
Great picture. No delays or skips.
I'm sure it helped that I upgraded to Uverse (12 Mbps) from my old DSL line.
Previously I suffered from those mid-play freezes, watching on my computer.
The game wasn't bad either (the end certainly wasn't).