It's a CCW light, not a dedicated weaponlight, so it has some drawbacks due to its size and battery. It's still better than not having a light at all. It works fine within 50 feet.
Mine has been fine through a couple thousand rounds, until just recently. Took it out, tested the light, didn't work. Changed batteries, worked for a few moments; then it cut out, thumb switches and crossbolt. After scratching my head, I smacked it, and suddenly, it worked fine. Checked the other battery that had been in it for months; still works fine.
I have since cleaned it and checked it again and again, hasn't cut out on me a second time yet.
As another poster said, check the battery compartment. If it just needs to be cleaned every now and again, that's nothing. If it has problems with not working for unknown reasons, then it needs to be shitcanned. Even so, it doesn't bother me too much, since I carry a handheld light that I go for first, anyway.
Next time I have a problem, I'll ship it back to Surefire and find out what the issue is.