Likes the rubber strap mounting gives flexibility enough to mount on a seatpost or chain stay. I do both depending on which bike I am riding, and this is great. The light can be very bright and visible. It has multiple settings.
Dislikes It has multiple settings, which is cool, but it has too many (11 different settings), which is nonsense. Three or four would be fine. It took awhile to find the best setting for me, which balances brightness with battery run time. I don't love the recharge method (has a USB nub that make you plug the entire light into a charger, rather than a cord simply going into the light).