The KeyMates do start out very bright, but after the first 45 minutes to an hour they fade VERY quickly. For the same price range of a KeyMate, I'd get an Ultra G (although it's considerably larger...), or one of the Dorcy 1AAA lights. They're really good lights for $6.00, and it's "bright" run-time stomps the KeyMates'. But if you want the best true keychain sized light, and aren't afraid to part with 25-30 bills, then get an ArcAAA. You WON'T be disappointed...
PJD
P.S. If you do get a KeyMate, I'd recommend the titanium finish. The coating on the black one gets scratched off in your pocket quite easily.