I'm very much like you in the fact that I was trained using the traditional grip. I stayed exclusively on this grip until about a year and a half ago. Then I started to train myself using matched. I did this because I've always had a problem with playing fast (e.g. really fast 1/16 note triplets around the kit). The problem was not exclusive to moving around the kit though. I've never been good at single stroke rolls
I'm now comfortable using matched and believe that I am a better rock/progressive drummer because of it. I still switch to matched for more subtle playing (e.g. jazzy sections of a song or some sublte snare work). Matched did improve my speed for which I'm gratefull.
I guess at this point I believe I am more expressive with traditional grip but can play more powerfully with matched.
The only specific advantage I can point out is that I've always found hitting crash cymbals with my left had in the traditional grip to be awkward. It seems much more natural in matched.
