I have had few LED mini flashlights that didn't have switch problems or problems with the connection on the battery cap. Until recently, the LED Mini Mag-Lites were the most reliable, but I almost always had to loosen and then tighten the battery end cap to get them to work. I now carry a mini flash lite by Coast that uses a single AA cell or an AA size Lithium Ion rechargeable cell. I know it's not an AAA cell, but they haven't failed me yet and they are very bright when used with the Lithium Ion cell. The 14500 Lithium Ion cells are 3.7V instead of 1.5V, but the flash lite will use either one. I carry one of these Coast lites on my belt all of the time. Around here, I get them at Menard's, but they should be available elsewhere. The one that I use is an HX5. I have yet to have any problems with Coast flash lites or headlamps and I have several. I have a couple of inspection lites labeled Snap-On that use two AAA cells and work very well, but don't seem to be available any more. I think that they were special marketing deals.
For more than ten years, I have carried a Petzl Zipka headlamp in my pack. It uses three AAA cells, is very reliable and very compact. The Zipka is not like most headlamps and you really have to see one to appreciate it. There is no adjusting or fumbling with the straps, just pull it apart and put it on. Altogether, I think that I have three of them. One in the pack, one in the truck and one in the drawer upstairs in case the power goes out.
For more than ten years, I have carried a Petzl Zipka headlamp in my pack. It uses three AAA cells, is very reliable and very compact. The Zipka is not like most headlamps and you really have to see one to appreciate it. There is no adjusting or fumbling with the straps, just pull it apart and put it on. Altogether, I think that I have three of them. One in the pack, one in the truck and one in the drawer upstairs in case the power goes out.