Naemanson, Definately MiniDisc, I have a Sony MZ-R900 that has the *4 long play facilities,and the quality on that setting is still better than casettes abd it gives about 5 hours of continuous recording.
and a good compatible mic, it has a rechargable internal battery and I have 2 spares, but it has a "piggy-back" AA battery pouch that even with the rechargable FLAT will keep it going so you can carry on without recharging!! with a full charge and an AA in the pouch it will run for up to 17 hours!! You can use the software in your computer to enhance faint recordings and "Normalise" the recordings also( that is boost the recording to its max without distortion) and , because it is digital, there is very little "noise"when you boost the recording!
Micca( who is currently processing about 12 hours of wonderful chorus singing from towersey Folk Festival)