I prefer AA lights. I have a FourSevens Quark AA - currently sitting unused. And I have an Olight T15 - currently sitting unused.
The one I carry every day is a cheaper light from China. I like it better. An XTAR, model WK41 (single AA-sized cell model).
http://www.xtarlight.com/05-chanpin/p-001-1.asp?styleid=259I don't like the two-handed operation of the Quark and Olight. You have to twist the head to change modes. The Quark cycles through two different sets of modes via pushbutton, the particular set of modes you cycle through being dependent on if the flashlight head is tight or loose. The Olight turns on/off with a pushbutton, but cycles through modes by twisting the head loose then tight again. I do not like the way they cycle through modes, where you always end up having to go through the annoying and useless flashing modes as part of the cycle.
The XTAR has a side pushbutton for on/off and it remembers your previous mode. A single click cycles between four brightness levels without traversing the annoying flashing modes. The lowest brightness is quite low, great for a "get up in the middle of the night" light or for when you really really want to make your battery last a long time. With 14500 LiIon rechargeables the brightness range is 3-300 lumens (Chineses lumens, that is) and 3-150 Chinese lumens with alkalines. To turn the XTAR off confuses many people I hand it to. It's a "push and hold to turn off" feature. People aren't expecting that on a flashlight, and generally hand it back to me still lit saying "how do you turn this thing off?" The XTAR still does have all those annoying flashing modes if you really want them - you double-click the switch to get there. So it's a totally one-handed light. Single click on, single click to cycle through modes, click-and-hold to turn off. Double-click to access the seldom used flashy modes. There is no momentary mode like some lights have by halfway depressing the switch. If momentary is important to you, don't buy the XTAR (I don't know if all of their models lack momentary, but my WK41 lacks it). Additionally, the switch will glow red when your battery is getting low, and start flashing red when it's almost dead. Very handy to know when to recharge. It takes alkalines (1.5v), NiMH (1.2v), lithium primary (1.5v or 3v) or rechargeable lithium (3.7v).
Despite being a less expensive and made in China light, it is very solidly made and I carry the XTAR in preference to the FourSeven and Olight.