I had a chance to compare the Planet Bike Rear Rack Blinky 5 against dozens of other lights during Wednesday evening's Ride of Silence. Several folks took photos and videos and comparing my lights against others, they're all about equal in apparent brightness.

The Planet Bike light is brighter within a narrow aperture, typically what a motorist would see from behind -- it appears like a brighter horizontal line a few inches wide. From other perspectives/angles of view, it appears somewhat less bright but diffused and still visible.

One photographer caught a couple of snaps of me from behind under a dark underpass, and my combination of Planet Bike Blinky 5 on the rear rack and Blackburn 2'Fer on my helmet, and smaller blinkies on the rack and seat stays showed up well, especially compared with the cyclists using only a single bright blinky on their seatpost, seat stay, etc.

So I'll keep the Planet Bike like. I'd rather have had a AA battery model and might eventually get the Serfas TL-STP. But the Planet Bike light seems good enough for my needs for low light and nighttime use.