People on Candlepowerforums claim that Sanyo Eneloops are the best brand of LSD batteries. I've been happy with my AA and AAA Eneloops. The AAAs last forever in the original PBSF. I saw a news blurb on batteries and how environmentally unfriendly they are. The only non-rechargeable batteries I purchase are the 2032/2035 coin cell batts that are used in cycling gear.

If you look at battery levels and amount of light out of a flashlight, they ALL drop off quickly unless they are regulated. Most cheap lights are not regulated. The Lezyne Superdrive is reported to have large light level drops.

Doh! I use 9 volt primaries in fire/smoke/CO detectors and DMM.