NB, I'll be using 'walkman' (no capital) here as a generic term for a pocket sized personal stereo such as ipod, jukebox, and mp3 as a generic name for digital audio file such as wma, flac, &c.
The crux of this, is the upgrade has reduced functionality, as it sometimes does. I'm not happy about it.
Mp3s have lost something compared to minidiscs. And I suppose I'm thinking of this as an archive format. MDs were the high point for me, I think. MDs were fluid in a way that virtual (in the as opposed to tangible) media aren't.
The advantages of MDs were numerous; encased in a cartridge, they were sturdy and kept the data away from grubby fingers, a move abandoned for god knows why when DVDs came out, which were very expensive and needlessly fragile. They were better than tapes because they were better quality. They were better than CDs because they were smaller, and instantly writable. And as I look back back, they're better than mp3s because they're instantly editable.
It seems like you've got a lot of control over mp3s, and in certain areas you have; shove them on the Internet, move them around your computer, edit their metadata, stock your entire music collection on your walkman, all great. But I'm someone who records audio from a variety of sources, not just CDs. I rip vinyl and listen to it on the move, because it sounds better. I record broadcasts and concerts. Do you know how hard this is with mp3s?
The one button that makes MDs better than mp3s is 'track mark'. Recording audio into a computer is easy enough, it's what you do with it then, the software, that's the trouble. I can't just take an mp3 of a performance, and just split it up into its constituent parts; I have I cut and paste it into several windows of audacity or whatever, then render each one to a separate file, then edit the metadata of each one. On MDs it was as simple as pressing 'track mark'. Even without a keyboard, md players seemed so much more user friendly, even before you take into account what they crammed into a device the size of a phone; line in and out, mic in, headphone out, optical in and out. Whatever you were recording or editing was a cinch. Give me a solid state mp3 player/recorder with the same controls and connectivity, plus a USB out (instead of eject, I suppose), and I'd be a happy nerd.