I've been using PT extensively for over nine years. I play only the piano, but have used PT to write and/edit scores for accompaniment (voices, bass and rhythm). I use it mostly for editing my inevitable mistakes in midis I've recorded live (is anyone perfect?).

By editing, I mean changing the velocities of notes, copying and pasting in intros or endings, or combining several takes (selecting the best parts).

As a primarily solo player, it's really all I need - plus a good piano sound.

Glenn

PS - I use Pianoteq for the piano sound - the onboard sound of digital pianos is lifeless and boring, and they are all looped. Samples have reached their peak - their sound isn't going to get better than it is, and the next edition of Pianoteq will make samples sound like the old technology it is.