Hi Steve, that’s a good idea!
Well let's see. Here’s my strictly personal opinion/comparison.
EASY OF USE
The Minibrute wins hands down. Super easy, intuitive and totally hands-on. An MS-20 requires quite a bit more know-how and experience, especially because of the modular styled patch system and some rather cryptically named knobs.
HARDWARE
The Minibrute has an excellent feeling keyboard, but it has only two octaves. The MS-20 mini has mid-size keys that don’t feel that great, but: there’s three octaves which might be more useful for lots of musicians.
The pots of the Minibrute seem much sturdier than those wobbly MS-20 mini knobbies.
SOUND & POSSIBILITIES
In general I personally think the Minibrute is a lot more "allround". It can coax out a vast variety of sounds and timbres. It can sound filthy and mean, BUT other times also really sweet and musical. The MS-20
too is capable of lots of different stuff, but it always has more of an edge. It's grittier. To put it a bit bold: an MS-20 always sounds like an MS-20, no matter what. Imho. Ymmv. But the Minibrute can sound totally unique, or like a late 70's Roland, or a Korg, or a John Foxx-styled MiniMg, etc...
Also: the Minibrute has separate envelopes for VCF and VCF, and two different envelope speeds.
It also has the arpeggiator of course, which is great fun for jamming.
On the other hand the MS-20 has one oscillator more, which opens the door for lots of other cool possibilities of course.
On a sidenote: the MS-20 mini has more (VCA) hiss than the Minibrute. It’s clearly noticeable at certain settings. You'll have to live with that. The Minibrute has no hiss, but sometimes a bit of “oscillator leakage” at higher pitches.
LOOKS
A matter of taste of course. For me, the MS-20 wins in this department because of its badass black industrial look!
Hope this helps you somehow!!
But don’t ever get rid of your Minibrute; it’s one of the greatest machines of the last 5-6 years