I used to only play matched grip, but after taking about 3 years off from playing I started with the traditional grip. Matched is still a little more comfortable in regards to speed around the kit for me (think early Dave Weckl recording customs setup), but I find that the trad grip gives me more options in the long run.
For jazz, I play only trad, for rock I'll switch back & forth as needed in the middle of songs or whatever. If I can get my chops up with trad to the level they're at with matched grip, no doubt I would play exclusively with traditional grip.
If I had to make a decision I'd say with practice speed and heavy hitting are not an issue playing traditional grip. Dave Weckl & Vinnie both play trad, and I've seen Steve Gadd play traditional grip in both jazz and rock gigs. Not to mention other great drummers that I know I've left out here.
That being said, the traditional grip also offers more options, one example being ghosted notes on the snare. Just a flick of a couple of fingers gives complete control over nice strokes that can be tricky playing with the matched grip without relying on the wrist (i.e. more effort) to compensate. After playing 14 years or so matched, I can still see how effortless traditional grip is in the long run compared to matched.
As for the "looking cool" factor. Watch some Buddy Rich or Gene Krupa and tell me that ain't cool!

If I see a rock or even a metal drummer playing traditional grip, I think THAT is cool shit! I don't know why, but to me it shows a different level of attention to details in technique, musicianship, and love for the craft and instrument. Don't decide on which grip to play because something "looks cool"......pick your poison, learn it to the best of your ability, and school everyone with your chops!