The dilemma for me as a percussionist is time management. I always sit down at the drum set first, and then look around guiltily at the marimba, xylophone, timpani and vibraphone. I play all of them, but never feel as though I put in enough woodshed time on the keyboards or timpani. Since the drum set is my first instrument, followed by timpani, I will always be drawn to those instruments first, out of habit.
Having said that, I know that my playing and teaching life is richer for having studied mallets. It helps me as a drum set player and teacher to understand and teach phrasing, melodic development, harmonic structure and song form, to name just a few things. As a drum teacher in Raleigh, I have students who play in every kind of band or ensemble imaginable. They need to know how to follow a song form and how to create fills that create smooth transitions. They also have to be good at sight-reading. Understanding song form and fundamentals of music theory and harmony can help drummers and percussionists to do those things better.