Hi all, I've been using The digitech vocalist for quite a while now with success. It follows your guitar chords (also will follow a simple piano chord, or any other simple sound with at least a triad), the cleaner the sound the better) I play several instruments, so what i do is create a track for the vocalist to "listen" to in RB,sending it out on a seperate audio channel to the vocalist. At this point I am not "tied down" to feeding the vocalist what it wants to hear to work correctly, my track does that, freeing me up to do whatever i want on the instrument I'm playing at the time and still have the harmony i want. Works great. As to MIDI, I just got the new vocalist VLD3. which actually will harmonize according to the MIDI notes you send it and not the sound, if that's what you want it to do, so you can create any harmony you want just using MIDI notes. All settings are MIDI controllable, so you can turn it off and on, add reverb, change the harmony structure and all other functions using MIDI CC controllers. Awsome unit. I also control my DMX lights through MIDI commands. And basically at this point, using RB, I can start a song, and everything happens for me, no pedals to push, no light switches, no guitar pedals, (as I use Guitar Rig4 alongside RB and control the program changes on it through a track in RB.) Takes a bit to program all this, but in the end is completley worth it for live use.