I wanted a rear light that I didn't need to remember to have to switch on and this works perfectly. I leave it attached to my bike and the auto on/off works great for my early morning rides.
Obviously the other primary consideration is visibility and whether cars can see it. On one particularly foggy morning ride I had a car pull alongside at a stop light and shout out that they could see me from "miles back". Sold!
I use this light on every ride. The battery life is excellent so far. I have used it for 4 12 hours and it was still as bright as when I started.
It turns itself off and on with motion , which works fine and saves battery life.
It will turn on if you are transporting it in a vehicle and hit a bump, but it has to be in the mounting bracket for this to happen.
A great light and I trust the research that went into the flash pattern.
The Light and Motion Pro switches easily and quickly from bike to bike. The light is very bright and pulses at different speeds and intensity. The light can be removed with a quarter-turn and put in ones pocket when away from the bike. On the road, I feel safer with this light than any other I've found.
I use this light commuting to work. It is completely dark coming home in the winter. This light is very bright, light weight, rugged and easy to use. Drivers give me plenty of room because they see me from a distance. Highly recommended.