I have noticed that MC11 lacks a lot in terms of DVD playback functionaly when compared to other tools like WinDVD or PowerDVD. The navigation system isnt as effective and the video playback sometimes gets choppy even on barely scratched DVD's??
Media Center does not have it's own DVD decoders, so uses those from something else you install
whether that be WinDVD, PowerDVD or something else. Therefore it shouldn't be choppier on Media Center than PowerDVD/WinDVD unless the system isn't keeping up for some reason.
Media Center is possibly a slightly heavier resource application(although compared to most still very light), since it's a full Media Center application as opposed to just a player, so if the system is running at it's limits it will probably start getting choppy.
What Navigation problems do you have?
I find it just fine. Although being an all in one style tool it's probably not going to have quite so many
options as the purpose built DVD playing software for playing DVD's...