The good: the light is easy on - easy off the bike. It's a pretty bright blinky for what it is... can see it coming a long way off, and works well to be seen for such a small light.
The bad: maybe it's a bad one, but the thing goes through batteries like crazy. I don't think it uses so much power, but it randomly turns on and off when just sitting there. I've taken it off the bike, and had it sitting on the table... off, and I walk back into the room, and it's on. So I turn it off, and make sure it stays off and walk away. And then I come back into the room and it's on. And then while walking over to turn it off, it goes off again. Hitting bumps on my bike will make it either turn off or on.... $28 is waaaaaaaay overpriced for this one. $5 maybe, but you need to make sure you remove the batteries whenever it's not in use, and that can be a pain.