Originally Posted by
Koyote
Nope. It's about the usefulness of taillights, even in daytime. In fact, I have another 100lm taillight (Bontrager) that is even more visible than the Cygolite due to the way the lens focuses the beam -- and I suspect plenty of other brands produce good taillights, too.
I use Cygolites on all of our bikes as day-time running lights. It makes me visible under the redwood canopy. I've had numerous people thank me for using them. I have never found a different light that I would use to replace/upgrade mine. They are worthy of any free advertising you can give them. They are also really versatile in terms of mounting to bike racks, seat packs, seat stays, etc.
The only one I have even considered as a replacement is the Bontrager one, but I think the Cygolites have better mounting options and give you more bang (photons) for the buck.