i for one loved my MD player. ran basically forever on a single AA battery, reusable disks that could hold quite a lot of music (several hours, if you dialed down the quality), could do line-in recording etc.
The problem wasn't so much with the format, but with sony's fucked up software. (also the plummeting price of flash storage didn't help with adoption)
But the format itself was nice. A durable, reusable disk, with a a pretty small form factor.