I'd be highly critical of the "can't be fixed" comment. Some of the later Moogs (again, made after Bob left the company) really are a nightmare to tech. Rat's nest cabling, not designed with an engineer in mind, etc. That'd be the memorymoog, minitmoog, etc.
Earlier stuff is well-designed, with all discrete components, which actually makes it quite easy to tech.
The Minimoog is the Moog sound. It sounds awesome, and will do wonky midrange stuff, high leads, and thunderous bass with ease. You can also run an instrument into it to make use of its filters. Nice!
The Rogue is smaller, and only has two oscillators. What this means is that, generally, the sound won't be as thick and rich as the Mini (which has three oscillators.) But the Rogue does have Oscillator sync, which can sound warm and vocal-y or screaming and ripping. (The Cars song "I like the night life" or whatever, uses oscillator sync on the main synth sound. Also, the synth breakdown in Emerson, Lake, and Palmer's "Tiger in a Spotlight" uses it to sound like a screaming cat. (That was on a Moog modular, but that's what oscillator sync sounds like.) Very nice, and a source of aggressive and expressive sounds that a guitar just can't make.
Modern virtual analogs can often sound quite good, but they just ain't analog. In general, their oscillators start to wound weird in the very highest octaves (and in the harmonics of lower notes, too, due to aliasing), and they generally can't do an oscillator sync that sounds as raw and ballsy as a real analog. 90% of the time, though, your audience won't be able to tell the difference. A real analog is for somebody who wants that final level of quality and realism. When a good digital photo just won't do, you want an excellent oil painting executed by a master artist. Most people won't care to look for the differences, but it's all in the details.
The MS-20 will be coming out in software soon, if that matters to you. It'll come with a mini-ms-20 controller that plugs in via USB. Nifty and kinda weird. Ain't a Moog, but nifty.
Obviously, this is coming from a true analog-head. I love my Moog, and I'd buy more if I had the resources. If this is your first synth, you may want to buy a digital synth. But if you have the basics covered, and want something sublime, responsive, and that sometimes pushes back when you push it, get a real analog.
-Hoax