I have a Cygolite 150 and a Bontrager Flare R. The Cygolite is 150 lumens and the Flare is 65 lumens. Of the two, I prefer the Flare and think it is a more visible light. Bontrager put a very nice lens in front of the LEDs and it shows up as a high bright larger dot than does the Cygolite that shows distinctly the 4 LEDs. I can tell very little difference in brightness between the two when looking at them behind but my eye is more drawn to the Flare. I think this illustrates the benefit of lenses vs pure output power.

I also have a See.Sense rear taillight that is supposed to put out 200 lumens. I'd put it third behind both the Cygolite and the Flare. There is virtually no lens over the LEDs and they look like tiny supe rbright pin points of light but less noticeable than either of the other two. In the taillight world, the lumens war is winding down and it's going to be a battle of the optics.

I have not had good luck with the Cygolite brackets. They are kind of fiddly and I've had them break before. I think the Bontrager bracket is inherently better and more robust.

I also do not like the two button interface on the Cygolilte. I wind up dimming it or changing the mode instead of turning it on or off. So it's more fiddly and I don't like that. The Flare has a simple one button interface and it's a lot easier to use.