well, I know a part of the problem here is that there are really three programmes running - Finale, then GPO, and finally HumanPlayback.
I can imagine the difficulty getting all that to function together.
I've been using Finale 2007 for several days and overall the experience has been good. I can't get the snare drum rolls to function (dynamics changes)very well. This has been one of the most noticeable problems so far. Tympani are working well in that regard.