I just got my 26650 flashlights a week ago and they are a pain but they're very effective. I wouldn't say they're dramatically cheaper either, by the time you get done adding batteries (15 per cell), a charger (25 for a decent one) and all the other stuff.
If you like fiddling with stuff, get the flashlights. You can also use them as... flashlights. Way better than the collection of maglights I have laying around.
If you want something you can just mount and forget about, get a regular bike light. Cygolite, Lezyne, Magicshine... there are plenty of good ones out there and they take some of the effort out of lighting your bike.
I agree with cycommute about the mounts, they're not great. I don't think swapping batteries would be any big deal though - unscrew the endcap, swap them out (they're FAR from small), screw it back on. Lather, rinse, repeat.