minidisc has a lot going for it. you can easily carry a few around with you. you dont really need to carry the outer cases. you can put some album art directly onto them. if your player has netMD support then you can just use a web browser to manage the tracks on a disc.

the only downside i can think of is the loud screeching every once in a while when the disc is seeking. but that could just be the player that i have maybe