Have used this light for years now and love it. Hours and hours of staying power. 5-6 hour rides no problem. Really like being able to lift the light out of the bracket to charge so no messing with remounting it to the bike.
Versatile slim design allows seatstay mounting so my inner thighs don't rub it like some seatpost mount lights. Very good battery life. I wish it came with another slightly smaller o ring for more secure mounting on slender steel seatstays.