Mountain Lion, iTunes, Bit Perfect & gapless playback
I found my first glitch since I upgraded to Moutain Lion.
Technically I guess it could be an iTunes problem, or even a Bit Perfect problem, though it's only started to manifest itself after I installed Mountain Lion.
In a nutshell, transitions between tracks on gapless albums (all ALAC rips of CDs) are not as smooth as they were. It's like iTunes (or the OS) is not telling Bit Perfect what the next track should be in time for it to queue the track seamlessly.
The workaround seems to be to drag the album you want to play gaplessly into a new playlist and play it from there. In my case, this happens automatically if I control iTunes from my iPhone's 'Remote' app, because iTunes creates a temporary playlist of the tracks it expects to be playing based on the selections I've made on my iPhone. I assume iTunes will do the same if controlled from the Android app as well, but I can't confirm.
I hope this helps someone.