Nah, I've had no issues with the Minimax software on Win7.
I hardly ever used the software, actually. I use mine as a standalone synth. There aren't THAT many features buried in the software. All the effects are available with button presses on the synth, for instance.
Nothing you'd use actively while programming, maybe just changing some parameters like how the note priority should work.
It's a great way to store your sounds though, just send them straight to the software and store. Load up the software and send them back to the synth instantly again, you don't even need to store them on the synth itself then. Much more convenient to use as a sound browser, rather than remembering if "Big mini lead" was on position 11 or 25 in the synth's memory.
I really like the Minimax sound, I've never played an actual Minimoog, but heavyweights like Sound on Sound and Sonic State have both claimed it sounds and feels almost indistinguishably like a Minimoog. All the minis sound a little bit different though, different matched transistor pairs and whatnot. The SoS tester said it sounded like one of his Minimoogs that always stayed in tune.
I borrowed a Pro 12 from a music store over a weekend to test it, was very impressed with the sonic presence. But found that I don't really need another 2-oscillator polysynth when I already had the Andromeda A6.
It's also polyphonic, so it can go far into Memorymoog territory too. Can't do unison though, that was never a Minimoog feature

Of course the Pro12 does unison like a Prophet-5 would.
SoS was also very happy with the Pro 12 ASB. You can find the reviews in their archives now.