In general, I agree with Old Roadie's review of this product. I bought two sets of these - one for my wife's ancient Suteki mixte frame commuter and one for my son's Modikoso framed road bike. The rubber attachment for the front lights render them difficult to remove for charging and the rubber must be stretched over blunt prongs to secure the light. I've had one of the rubber straps' prong-holes break through - it's a wear issue and should have been an obvious weak spot to reinforce or simply rethink the attachment arrangement. As with the Blackburn Flea lights, once the attachment breaks, no replacements are available and the light becomes useless. As Old Roadie said, the back light doesn't provide very long light - we only use them set to blink and they are difficult to power off. You've got to press the light against the tube to which it's attached to get it to power on, change mode, and shut off. Again, the attachment piece is super flimsy. I do find both lights to provide adequate brightness for dawn to dusk riding. Wouldn't rely on the front light to illumine a nighttime ride. If you can pick up a set for cheap, probably a good buy.
Front is v. good light, easy to attach, adjustable angle, bright enough for daytime use, and lasts long enough (on blinking) to last many hours.
Rear is so-so small and light, but that means there isn't enough battery power to give a bright light for very long, even on blinking, only gives about 3 hours. Hard to get it to turn off.