1: Halo B on "Pure Energy" rechargeable Alkalines.
Shot about 16K with them. NO signs of slowing up. Halo was still feeding 21ish bps after that.
2: Revy w/X Board on 2 9V Duracells.
Shot about 5-6 Cases then changed. Red light was annoying me.
3: 18V Shredder w/ 2 9V Duracells.
Still going stong 4 years later. Don't ask me how or why. :p
Overall, I much prefer the Halo B to any of the loaders I have used. Overall, most balls fed per dollar spent on batteries.