I still like the MS-20, frankly. Over the years, I've had four...two were the original version 1, with one of those being bought new back in 1980, and the other two are sitting on the other side of my studio right now, with those being Minis. You hear a lot of hot poop about how the Mini doesn't sound right, etc etc etc...
BUNK! What they sound like is a NEW MS-20, and NOT one that's been sitting around for 40-ish years. You have a lot of "VITNAGE RAR W0W"-types who claim that the Mini doesn't sound like it should. But lemme tell ya, if you went back in a time machine and unboxed a virgin, straight-from-Hamamatsu '20, it would sound EXACTLY like an MS-20 Mini. No lie.
Granted, yes, a proper modular is always better. But there ARE things that the MS-20 can do that modulars CANNOT. For example, that screwy input section that most people ignore. The idea was to offer a pitch-tracked input channel...but like Korg's other contemporary pitch-tracking device (the X-911 "guitar" "synthesizer"), it was utterly useless for that. BUT...that input section is made of pure, uncut ABUSE POTENTIAL, and a certain Mr. Richard James found that if you feed it UNpitched material, such as a TR-606, you make the MS-20 GO BERSERK with just a little bit of patching. If the TB-303 is the "lead" for ACIEED, then the mangly MS-20-processed drums is its complimentary backbeat.
Unfortunately, Korg continues to screw up...I just saw some demos of their new sequencer, and frankly, I thought it was a trainwreck. It might have ample connectivity, but it was obvious to me that certain parts of the sequencer implementation are not as intuitive as they need to be. It was like Korg was trying to either build a Beatstep Pro or a Polyend Seq, and wound up creating both...and yet, neither! Pft.