Jan,
I had answered your question this AM it was as Mike said. I went to post it and PG site went down. Just got back on.
If I could have afforded it I would have gotten the Voice Live 2 for all of it's flexibility. The GXT is the same harmonizer though so went with it. It also has more features then the M. I didn't cre so much for the Voiceworks. All three in the same price range. With BIAB you will need a midi unit to get the chords. I use RealBand so sending a silent guitar track to the guitar input is a cinch.It never missed a chord. Even if there were more then 1 chord change in a measure. Using a RT acoustic guitar is ideal for this thing as it's very straight ahead and steady. Unlike if you're playing it yourself.