The UltraFire was OK for a 2nd day on the same set of AA NiMHs. However, the switch is quite erratic. I probably had to whack it 20 times on the 40 minute ride to get it back up to full brightness, and one time when I hit a bump it jumped about 3 modes.
I think the Q5 is an acceptable headlight, but I'd probably go for a single-mode, more durable switch model next time. But if I had to go with something like a Fenix at $60 to $70, well, I can buy a NiteRider MiNewt USB for about $80 and get a hell of a lot more runtime and better mounting options.
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Work: the 8 hours that separates bike rides.