for some reason it wouldnt let me vote.
i have both and i prefer mini disc.
the main reason is that instead of having to take old songs off to make room for new ones i just pop in a different disc.
the discs depending on what mode you record it in can have 80mins, 2.5hours, or 5hours worth of music on them. you can record over songs on the disc as much as you want, change the order of the songs, group songs, etc. also, the discs are fairly cheap.
of course you could get one of those mp3 players that hold like a million songs but those are expensive; its probably a pain to search thru all those songs too.
i have the sony net mini disc player and the samsung yepp mp3 player.