Pye and the guys from SLRLounge have done us a huge favor; they went out and bought a bunch of different AA batteries to test and see how well they perform for our camera flashes. I wish the tests were more thorough, in the sense that I wanted to see how consistent the flash was pumping out; however, their tests did conclude that some battery brands are just absolutely bad news, like the Energizer and the Kirkland. In terms of heat and recycle timings, Pye concluded that the Sanyo XX Eneloop (rechargeable) is the best out of all the candidates. If you’re looking for non-rechargeable, you should go with either the Sanyo Eneloop standard, or the Duracell Coppertop.
Be sure to check out SLRLounge’s full detail report on AA batteries.