Whichever method you choose (I'll add a vote for minidisk) practice first and then practice some more until handling the machine becomes second nature. There's nothing worse than starting to recird and then finding that you've pushed the wrong button and didn't record anything.

Get a machine that has a manual recording level control as well as automatic. On certain stringed instruments (piano is particularly difficult) the AVC can be fooled and you will need to set the recording level to about half what the meter says so that the harmonics are recorded faithfully. Again practice, practice, practice.