Several threads on the Ultrafire lights.
Here and
here. Upshot is it's a nice light but may have flickering problems which can be corrected with a small amount of effort.
Once fixed, mine have output very simiilar to Fenix L1P, but Fenixes beat it for efficiency. 602A has much shorter run times (maybe 60%) than Fenix L1P. Others have found singificantly less output in 602A but slightly more run times - perhaps 75% of L1P.
One attraction of 602A besides cost is the head disassembles easily and the LED is accessible, making it an easy light to modify.