I "entered the game" at the age of around 8, many decades ago and hence have owned flashlights of every conceivable battery format including button cells, AAAs, AA, C, D, CR123s, CR2, 18650s, 6 volt lantern cells and others. One way or another, I have lights of all of these formats still in active service, including for example a couple of C and D LED converted Maglites. My primary "go to" workaday lights in recent years have been RC123, AA, 18650 and CR2 (keychain). Having said all this, if there was one single battery type I had to chose it would be AA, regardless of 2013 technology. I have always liked the format and have never been without several AA lights in my collection because these lights have always offered a good size to weight performance, even years ago (going back to say the AA Mini MagLite) and AA batteries are the most universally available battery type in the world. You can always find AAs in just about any store in any country. In a "true" emergency you could find working AAs in practically every household if you really needed them even if you had to scavenge them from a TV remote in a badly damaged home. For this reason alone, I have always made it a point to have AA lights in my collection. I get the OP's point about the vast improvements in AA performance but for me the enhanced performance has not been a question of "switching" to AAs, it's really been more a question of the ability to go with a one cell light like the Zebralight SC51/52 when previously I might have opted for something along the lines of a Quark 2AA of some emitter variety.