I have the USB front light. The rear seemed a bit "nothing special" on the display, but perhaps the battery was dying. I have seen worse rear blinkies tho.

I use the front light as a backup to my NiteRider. Often I finish my commute through City Park areas that are country-dark. I don't want to look like a freakin' locomotive rolling through the park, so I use the dim setting on the front flea. It also has a little piece of plastic above the diodes that keeps me from seeing the danged lit bulbs. Most other headlights seem to purposely spill light upward making it HARDER to see anything as I am partially blinded by my own light. I picked the Flea over other similar lights because of this feature.

During winter, if I take off late on my road bike for a long joy ride and suspect I could be home after nightfall, I feel confident that the Flea will get me home in one piece - with due care. If fits in my under-seat bag no problem. There if I need it, forgotten if I do not. It's a good light for it's size and I am not throwing away truckloads of those lithium watch batteries.

Finally, if I am riding through the Hood after dark, I can point the light downward and run on dim setting so as not to advertise my approach to those who would do me harm.