The Knog Blinder and the Planet Bike SuperFlash Turbo are not that great in broad daylight they almosts faded completely away in direct light, I've had both and still have the Turbo, in addition the Knog was poorly made and the switch actually failed 3 times but under warranty, I got tired of the problem and got my money back. The Turbo is also cheaply made but it's held up better than the Knog. The light I have that is very well made and looks like a roadside safety flare in the day time is the Light & Motion Vis 180 not the Vis 180 Micro. This light actually came off my saddle bag (due to me not clipping the clip shut!) flew onto the concrete while riding at 20 mph and didn't ever scratch the light; the Turbo by contrast has never fallen and the switch has 1/2 of the plastic missing, and the lid to access the batteries pops off just sitting inside my backpack! It will have to replaced either by the end of this season or next.

Serfas makes a really bright tail light as well called the TL80, I've never seen one in action nor used one so not sure how well they're made, but the reviews about it's light intensity have been very good.