I just got an EverLED in the mail and tried it in both my 2D and 3D mags. No beamshots, but they're both pretty bright - better than before the drop-in, but I think it's going to live in my 2D. For versatility, I'm going to use 2 NiMH Ds for runtime or 6 NiMH AAs (in holders) for power depending on application. I love the fact that it will take varied input! 9v is maximum, though, and you get diminishing returns as you boost the voltage...
Of course, if you really want power out of a mag just buy one of the Malkoff Devices 3D modded mags... $110, and the LED is rated at 240 lumens @ 1000mah, apparently will run for 6 hours at rated output and then diminish for some time. It's definitely on my list of things to get.