Very simplistic architecure: 2 VCOs (syncable) plus noise source, the abovementioned polyphony, and an extra oscillator called "bell tone", AR envelope, LFO (tri/squ/random waveforms, routable to filter and pitch), osc mixer.
Bass is definitely its strong point. This thing can rattle the windows. Great for dub, funk, drum & bass, hip-hop. (Mine is mistuned 5 semitones below proper pitch. I thought about getting it calibrated, but I like having that extra bass range. I might even see if I can tune it an octave below :) It's useful for bleeps and acidish leads too, but overall its palette is pretty limited.
If you own one of these, READ THIS:
There's a foam dust screen just under the front panel which turns into a horrible, horrible black goo over the years. GET IT OUT OF THERE!! Pull off all of the knobs and slider caps, open the case, and remove the top circuitboard. You'll see the foam overlay. BE CAREFUL - it liquefies on contact, and it's very, very sticky. Rubber gloves are a good idea.
Mine has 6 broken keys, but then a cat pissed in it. I play it thru CV anyway.
Amazingly, I've never noticed any tuning drift. Whereas my Moog Source takes half an hour to warm up before it'll stay in tune, this thing is very stable.
I have a peculiar attachment to this thing. (Maybe not so peculiar, since it was my first analog.)
Though it's rather limited, it's a great choice for a beginning synthesist, or if you're looking for a set-and-forget bass box.
I really want to stuff mine into a rack unit. I don't know if I have the nerve to take a soldering iron to my precious little EmGee tho.