FLAC is certainly gapless on Karma. The only one in that list which I'm not sure about is WMA.

Having said that, there's reportedly a bug where if you insert tracks into the playlist one-by-one (i.e. you always Insert or Append while the last track in the playlist is playing) then the intervals aren't gapless. I haven't got round to checking this out yet, but even if true it'll be an isolated bug, which doesn't affect other playback situations, such as playing a whole album.

Peter