Well it is odd to have this thread again. Way back I tried to get TC Helicon to answer a simple question & that is what's the difference in harmony between the GXT & the M. I received a reply yesterday. They say the M is identical harmony wise. I wish I would ahave known this. The GXT is really nice and I haven't had but a little time with it however at second glance the tracking is exceptional but not perfect. The M being MIDI is perfect. For a guitarist the GXT is the only way but I had to create tracks anyway to drive the GXT. I could have just as well done MIDI tracks. One other factor was I would have needed a MIDI interface. In hind site I should have gotten the M for use with BIAB or RB.