You obviously had ones that didn;t work for you. I for one regret their passing. The sound quality thing was hyped up badly. None sounded bad, all sounded better than cassette, and the ATRAC system worked pretty well. I had a couple of HHB portadiscs and they were great, and for live sound playout and local radio, MD was so good. Track renumbering and titling being the really, really useful thing, plus editing to trim off beginnings and ends. Quality was close to CD, and better than mp3, which everyone seems to not find a problem now? I don;t know why purists hated it so much. The 1U Sony's were brilliant. The Big Tascams did a great job with big play buttons, and the amateurs all used the domestic Sonys and Tascams happily because they could do what nothing else at the time could. Qlab hadn't been invented, so MD was the goto medium. Reliability was very good until it suddenly wasn't and most folk just threw them away, rather than try to repair them. Alignment was preset and while you could tweak, they were never reliable.
As a medium for domestic audio it failed miserably, but the sales to pro users were substantial enough to give them a number of upgrades, new models and continuation. They just didn't catch on with domestic users, hence why the multitracks came out and did pretty well.
I stopped simply because the machine supply dried up, then I simply moved to computers, where we are now. When computers were not like they are now, MD was 100% viable, sounded great and nobody ever complained about sound quality. The pros outweighed the cons by a long way.