I own the original Minimonsta (x86), and I do like it a lot. In fact I do prefer it to Minimogue and others that I've tried. That said, even at half off I don't think I'll be upgrading, $115 is more than it is worth to me right now.
If cash were endless I'd have all of the GForce synthesizers, and the TimewARP 2600 as well, but cash is not currently endless. And sometimes one needs to make choices between the best emulation, and good enough.
So what do I hear as a difference between Minimonsta and Minimogue? I think it has more to do with what I don't hear... there are artifacts (for lack of a better term) that I hear when I use extreme settings on the Minimogue. The Minimonsta works better with these settings.
Now I have to confess that I am not a Mini Moog guru, most of my time was spent with a Korg MS-20 and an ARP 2600. The thing that makes the TimewARP 2600 interesting is some of the old "tricks" - strange settings that none of the other emulations emulate<G>!
BUT, if you have some coins burning a hole in your pocket you can't do a whole lot better than anything from GForce!