Same experience as shortbread_fanylion here.
It’s very good for the money. Certainly when you put it up against some of the competition at over twice the price, you wonder where the extra money is going. It consists of one Seoul P7 4 core LED emitter, which I believe (though correct me if I’m wrong!) runs at approximately 12 watts.
It’s not the brightest light in the world, but it’s certainly plenty bright enough, and I don’t know of anything close to it in price that’s as bright (that’s bike specific at least). I prefer the floody beam myself, though I have ordered a Cree R2 250 Lumen (same LED as the Exposure Joystick) torch from deal extreme to go on my lid to provide a bit of extra light “where I’m looking” if you get me.
OK, a deal extreme P7 torch is going to be pretty much the same light, and half the price, but it’s also significantly more of a faff. The Airbike SL2 light battery is 3x 18650 Li-ion cells i believe, which means the 3 hour run time on full beam is realistic. Personally I could not be doing with stopping to change the battery over every 45 to 50 minutes (fully discharging a Li-ion cell damages them a bit) whilst on a ride, what a ballache!
Oh, and the Airbike is one of the lightest lights (as in weight) on the market, it’s less than 400 grammes all up and that’s including 3 Li-ion cells. Those P7 torches are about 300 grammes without a battery in.