I have used the MAX on and off since 1984, when I bought it used. I enjoyed its organ sounds a lot. I enjoy tweaking it with the following references:
MIDI controller messages from NoteIt: www.geocities.com/SoHo/2163/scicon.html IBM based patch editor: SixPat www.geocities.com/SoHo/2163/sixpat.html
I haven't tried this next mod, but probably will: Add SubOscillator Mod: www.geocities.com/SoHo/2163/6traksb.html
The MAX is programmable from a SixTrak (if you have one). If you want a real time knob board for MAX and don't mind building it yourself, look at my page www.geopath.com/~jraden/knobs.html. My MAX is starting to show wear on its buttons, but otherwise I love it, and plan to gig with it next month. It turned out to be more than I expected when I bought it.