I really like this light. I paid double for something practically identical about 4 years ago. The beam is fine for cycling at night, and the intermittent flash is great whenever you want to be visible during the day. I haven't used it much, but the full beam setting definitely doesn't last 4 hours! I would get less than 1hr on the brightest setting. Otherwise, the battery attachment is a bit of a faff, but once you get the hang of it, works ok. Be careful if the paint on your bike is delicate, though! The battery can move around a bit, so it can damage the finish. The light attachment itself is secure, though.
Fantastic light, not so long ago, you'd be paying serious dollar for a light so bright !