I was WAY into minidisc a few years ago. Now I'm convinced that it is insignificant. ATRAC data compression DOES NOT sound better than mp3, ogg, or wma at high bitrates, much less some of the LOSSLESS formats available now...such as LOSSLESS wma (which CAN be played by many portable hard disk and cd players.
The magneto-optical technology used in md is slower, more fragile, and has many limitations (in terms of editing, etc) when compared to hard disk based systems (or computer systems on which one would prepare files for an hd or cd portable.
Media sometimes fails. Ask a radio reporter who has lost an entier news conference because his batteries feiled before the table of contents could be written on his portable md recorder, or because the machine simply didn't write a toc. This is common enough that it happens to EVERY md user occasionally. It has NEVER happened to me with, for instance, my Archos Jukebox recorder.
Want removable media? You can get 8-12 hours (even 24 hours with wma) on a 50 cent blank cd, vs 80 minutes to 5 hours on a 3 dollar md.
I frankly hate the idea of abandoning the md format, because I'm heavily invested in it...with two high end "decks", two (one broken) portables, and even one (Casio) boombox. But this isn't 1997. There are better choices now. Even the radio stations which used to send audio to me on md now use other formats (usually either cd, or some compressed format e-mailed directly to my studio). So my poor old md gear sits idle, alongside my 3 head dolby s cassette deck, and DAT recorder...relics of digital's rapidly changing past, and testimony to how rapidly gear becomes obsolete these days!
Please, don't flame me. There is some excellent md gear out there, and it DOES provide superb sound quality (as does dat, reel to reel, and dolby s cassette!) It's just that, well, time marches on!