Sony made some really sexy devices, but the format itself just came out too late for it to have widespread consumer appeal. MP3 was just way more convenient, and a lot of folks still rocked discmans like myself.
That said: it was actually a very popular format for the media. I was a journalism student 2001-2005 and it was the format we recorded all interviews on. The radio station where I worked at had MD gear, but also used Marantz compactflash recorders, which I personally preferred.