I use brand name batteries, just depending on what I find. Energizer or Duracell, and it's usually worth the money to buy the 'better' versions of both.
Granted, I have been looking into rechargeables, because I hate having to buy so many batteries. But I also know that most rechargeable batteries run at a slightly lower voltage, so I haven't done that just yet.
2003 ICD BKO w/ 45/4.5k, Ricochet Apache
'98 r/f Autococker w/ 45/4.5k, J&J Edge kit (14"), Ricochet 2KX
PCS US-5 Mech. w/ 48/3k, J&J Edge kit (10"), cyclone feed, JCS folding voodoo stock with RVA
Kingman Hammer w/ 13/3k, J&J Edge kit (14")
Projects in the Works:
'99 r/f Autococker w/ 45/4.5k, J&J Edge kit (14"), and THE CYCLONE!!!