Hey again! 😉 The MT-100 is great, I've tried the old Sierra adventures like Police Quest 2 and some of the old Space Quest games, although Space Quest 5 and 6 sound like crap because Sierra was lazy and just remapped the MT to GM instruments. It really sounds AWFUL! King's Quest 5 on the MT-100 sounds A M A Z I N G!! PQ2, SQ3, LSL3 and SQ4 sounded awesome! I'm about to try my old Lucasarts games too.
I've always loved Doom, the old Apogee platformers (BioMenace, Commander Keen), Wolf 3D, Stonekeep, Deathtrack, the Sierra games , Lucasarts games (esp Day of the Tentacle and Sam & Max), Tex Murphy 3: Under a Killing Moon, even old Raptor and Wacky Wheels. I grew up with these when I was a kid and sadly I never had an MT-32, just the Sound Blaster's crappy FM synth. (and it was an old Sound Blaster 2.0 8-bit on my mum's 386). Many old games are more fun the crap you buy these days.
So yeah, when I said "best", I meant best for the majority of DOS games, like an "all-rounder" synth. I'm kind of tossing up between an SC-55mkII and an SC-88, maybe others.