have one of those Chinese lights for more than 2 years now and it served me more then well over that time.
Only thing I found annoying is, that when I use them during wintertime (temp. arround -10°C) the cables are refuse from beeing flexible (they tends to harden like a wooodstick) plus the connectors are not waterresistent.
beam and light pattern are good enough for me at all riding conditions in the night.
one month ago the battery pack seems to have a loose connection - sometimes the lamp works - sometimes not. So I checked the battery pack for some bad soldering at the print plate, but is was the print plate itself, as I was in a need for the lamp, I unsolder the print plate and resolder the cables to the batteries directly.
No idea what the plate is good for, but the lamp is working as supposed, also recharching works fine and the battery pack has not been exploded since then
Maybe someone over here can enlighten me what that printplate on top of the pack is good for (controlling discharge and recharge maybe ?)
Anyway you cant get wrong with one of these lights (some clones do have better batteries and battery management systems)