generally, for composing quickly, I prefer MIDI too. The realtracks sound great but they are too slow to work with, there's no easy way to discern where is whatever you are looking for, and cannot be edited easily if they have something in them that you don't like, .e.g. too many passing notes, etc

The problem with MIDI...the sounds suck so bad. But for writing music without taking 1 day it's still the best way to go.