Mixed review for this product. Some background: I installed this on my wife's bike. We typically ride early in the morning, starting at 5:30AM to 6AM, for 1 to 1.5 hours, 5 days per week. All city street riding. Wanted a light to illuminate the road close and far, plus some side spread. Also wanted a flashing mode for daytime rides.
First, the positives. The light intensity and light pattern are outstanding! I stuck with the original lens pattern; no improvement needed. At first I thought that the app's ability to customize settings was just a gimmick, but it turns out that I love this feature. Lastly, my wife loves the remote switch. She has some limited motion with her thumb, and the remote switch makes it very easy for her.
Now, the negatives. The battery life is way under the manufacturer's claim. I've used it for multiple charging cycles, as per their advice in their FAQs, and it hasn't improved. I find that after 4 hours on 10% power, I only have 35% remaining. Can't imagine what the run time is on full power. Also, the overnight temperatures in my garage are typically 32 to 45F and daytime is 40 to 60F. If you live in a colder climate, your run time is sure to be considerably shortened.
Next, the light loses 4-5% power overnight if you leave it connected to the battery. Finally, the light loses synchronization with the button overnight, even when I do leave it connected. This means that I have to go thru a resync procedure every ride. This involves unplugging and re-inserting the USB connection. It's unlikely to wear well. I expect that either the light side or the battery side connection will break within the year.
Gloworm is oh so close to a wonderful product. They just need to improve their battery management, which probably can be accomplished with a firmware update. (Turn off the wireless communication if the light is idle for 10 minutes. Restart it with a button press. Or some other solution, such as a disconnect switch in the USB cable.) I would not recommend buying this product until Gloworm recognizes and fixes this issue. If they do address it, or if you are OK with the limitations, then this is a top notch product.