For info, I have used AA's several times within my grip and they hold up pretty well. A single LPE6 has a capacity of 1800MaH @ 7.2v. Six standard Eneloop AA batteries provide 1900MaH @ 7.2v, so on paper offer slightly more clicks than an official battery.
In the real world I achieve ~400 clicks with a single LPE6, ~800 clicks with 2x LPE6's gripped, and ~500 clicks with a set of Eneloop AA's. This is with a large lens with IS turned on and plenty of screen use. My gut feeling is that the rated capacity of Canon batteries is optimistic.