I am a fan of the Tek Tite led replacements known as their LPR series. I have the 2 cell (3v) and the 4 cell (6v). I also have an EverLEd so comparisions are easy. First of all, the LPR's are about half as bright as the EverLed's to my eyes. That said, in darkness, I find the LPR's a lot less assaulting to my eyes. They are a milky white light that I find easy to see with. EverLed claims to give 24hours of good light in a 2D flashlight. I just completed a constant run test in a 2D Rayovac (their workhorse series reflector is ideal) with the LPR-2. It gave me 48 hours with only a little dimming and the batteries gave out at 60 hours. In my tec 40, the EverLed is also a lot brighter and dies in about 10 hours. The LPR-113 (6v) gave only a little dimming in the first 20 hours and gave useable light for another day or so. I also noticed the EverLed dimmed somewhat after the first hour or so. The LPR's do not.
So, I like them both. The EverLed's are very bright and versatile. The LPR's are a lot smoother on my eyes and burn around twice as long. To me, they fill different roles.
Bill