I play on hardcourts at altitude and use Dunlop, Penn, and Wilson high altitude balls weekly. For match play, none last more than a couple of hours. However, I have noticed:
Penn--dead and bald in around 1 hour
Wilson--bald at the end of the match, but still have a little bounce left
Dunlop--noticably firmer after two hours with more material left on the ball (although these balls are notably heavier out of the can)
Penns go into the garbage after one session. Wilsons go into the ball hopper for serve practice. Dunlops are used for warmups the next day.