One of the things I like about my DAT machine is that it has a digital out. With the optional digital interface, I can dump the data from tape to my computer without any loss of fidelity. This works great for sharing lessons I recorded with other people who were at the class. If you skimp on the mic to save money you will not be happy with the recorded results. Condenser mics offer the highest fidelity and strongest signal, but are more expensive than many dynamic mics.
Condensers give better results for room ambient recording.
Pzm mics are great for room ambient recording, but have a somewhat limited frequency response. Of course, the more you're willing to spend, the better frequency response you'll get. There's alot of difference in the models in between. The mic I use, the AT822, is stereo. While the stereo image is not as good as one would get with two independent mono mics spaced far apart, it is still very convincing and great for picking up everything in a room or small outdoor area.