I actually just bought a Light & Motion Solo Logic Mv (6, 10, 13W; 7.2v battery; lasts 2 hours on high; full charge in 3.5 hrs) tonight from my LBS. I took it out for a ride on moderate singletrack and it was great. I was on my new bike so I was taking it easy but visibility was awesome. I only had it on the handlebar but it still worked great...I have it setup on the helmet now and it should be even better for the tight, twisty trails I usually ride at night. I also took it down some of the steep valley hills and I was able to go as fast as I could in daylight. For the price, I am very happy with it...I got it for $225.