I tried one of these at Mayhem and there is plenty of light, you want a second light for racing as it can get a bit hairy at speed but for normal riding there is plenty. The very low weight means you just don't notice it on the helmet. The only gripe I would have is the run time, most of my rides take about 3 hours and no matter how you cut it you will be on a back up by then with the piggy back.

That is just super neat.  I love design solutions like that.  Well done the Exposure boys.  Looks like I have something to add to my Joystick this winter to keep in the running of the light arms race!

I haven't found a lack of power a problem with the joystick max, but as a helmet light think it spreads its beam to much, would be better if it was more concentrated into a spot.

Can the piggyback be used with a battery pack to provide an entry level (cheaper) version of the Joystick?  This would really make the top lights more affordable for the less serious rider.

I'd expect it could be, I've been meaning to ask Rory about the power port on Joysticks to see if it's possible to run GPS etc off it. You could drop him an email - at a guess, it's probably pretty much a direct connection to the internal battery.