I'm very interested in the new BIAB 2009 for Mac. I have a feeling there's a real limitation to the use of Real Tracks, though.

Do the performances in RealTracks only follow changes that occur on the strong beats of the measure? In other words, are the real tracks able to follow eighth note and sixteenth note pushes (anticipations) entered into the arrangement?

I'm guessing not, as it would probably involve totally new recordings of alternate performances. But I'd love to be pleasantly surprised!