I feel as though I'm able to say some legitimate things about this synthesizer. I've been using it pretty intensely for the better part of a year. The Roland ProMars is sort of the monophonic, "special friend" of the Jupiter 4. It does have the obligatory cv & gate ins and outs (see previous post). It is, I believe, one of only a few (and only Roland) truly analog (and by that I mean voltage controlled oscillators) synthesizers that has patch memory. This makes it ideal for live performance. It's "compuphonic" memory bank holds eight user patches and has ten preset sounds. The preset sounds are a mixed bag. The Brass sounds (trumpet, trombone and sax) are wonderful, the Strings sound is nice, the Piano and Clavi sounds are fine and the Voice sound is incredible! The Synth I and Synth II sounds are useless.
The patch memory is great, but you are unable to edit a patch after it's been saved (unlike a Juno-106 or Jupiter 8 for instance). So after a patch is saved, if you try to change most of it's parameters you're out of luck. Except! There are some performance controls that do still effect the saved sounds. Most notably: a little knob called Brilliance, that is essentially just another way to control the cutoff frequency of the filter. There's also an octave switch that can be rather useful. The one thing that ends up being a bother is that the envelope settings are completely fixed once a sound is saved.
All in all, I think it's a great synthesizer. If you're interested in a set, this along with the Jupiter 4 and CR-78 drum machine all have the same sort of design (1978).