okay, that's some info all right...
i followed those links and read up on some other review sites and am leaning, believe it or not, to the fenix solution. my rationale is:
a) it uses aa batteries, which are easy to recharge. i read up on the recharging of the niterider light and, man, that has to be the least convenient system i've heard of. that killed nightrider for me right there. besides, surplus aa's can be carried for backup. a surplus 9 hours of charging time can't.
b) it does not have an extra battery pack that you have to lug around like a rubik's cube of power. i did notice early on that all the stylish marketing photos of head lamps always had this wire leading from the light off the edge of the photo. hmm. to what, i wondered. to a wheelbarrow of batteries, apparently. yes, the fenix is bigger than the other lights, but it's all in one and doesn't have an extra battery box that connects by a breakable cable.
c) the livestrong mount system? simiple, elegant and appeals to my "ghetto sensibilities". it looks simple and leaves no mounting device on the helmet when the light's not on.
d) the fenix is a useful flashlight when not on the bike helmet.