MIDI was basically designed to put muisical instruments on a digital interface.
All of the sound is synthesized, so you lose some sound quality. The sound's
aren't as great as a wav file which can be recorded off CD. The goo thing about
midi is that it allows users to write their own music and let it  playback. Midi is
all electronic music. Some groups have great midi sounds, such as the Kurzweil
keyboards, and the sounds that are used for Broadway. These sounds sound
close to the real musical instruments. Most home users, however, have a sound
card that doesn't offer that many great midi sounds. But for the most part, midi
is a great compositional technique.