Good as in v. Bright with decent battery life. I don't like the head torches we are supplied. Super bright but short battery life, like one day and done. They are heavy too so prefer to use the flashlights. It won't ever be used on the bike but they look a good option and could get s couple st that price
They take 3 AAA cells. I use NiMH rechargeables. On full beam, I would probably get about 90 minutes of continuous use and on reduced power several times that.
Full power lights up a dark room pretty well and you can certainly see what you are doing on reduced power.
They are well made and surprisingly small.
I bought 2 and might buy another couple.
They are not bright enough for high-speed descents on the bike, but are great to be seen by and would work ok on slower rides down dark lanes. I think using 2 on the bike would be a good idea - one pointing just in front of the bike, and the other slightly further down the road with the beams overlapping to give a bright spot where you need it most.