My first bright LED flashlight was the Fenix 4n1 kit with a P2D Premium, 1xAA body/switch, and accessories. I learned two things - one being the utility of CR123s. The other was a quest for a larger light - that little Fenix got hot! I got a deal on a Surefire 6P LED - great light. I bought a 6P - expecting a high output 'drop-in' LED - eventually bought a Surefire P60L, giving me two 6P LEDs - one for each car. I liked that E1b, too...
Well, I scored one over two years ago - great light, whether checking the yard at night on high, or making a night dash for the toilet on low (7 cats to avoid in the dark!). It's been my EDC, clipped in my left front cargo pants pocket (RF for something louder...) ever since - and bedside light for that 'dash'. It's showing it's wear, but functions fine. Two years ago this Sept found me buying my 4" 617 - and an E2D LED. Sadly, I sprung it's clip and bounced it on a sidewalk it's first week - further crennalating that switch tailclap. I called Surefire - finally - and they sent me a new cap - gratis. I cleaned the rough edges on the old one - and the E1b sports it - allows vertical standing, ie, candlestick operation. While the E1b is rated at the same 80L as the 6P LED on high - ~4hr, it will put out 5L for over 1.5 days. The E2DL seems to work for 3+ days on low and 4-5 hr on high - rated at 120L but brighter than the P2D's rated 180L on 'turbo'. Folks have measured it at 170L. The latest version is rated at 200L - probably puts out 220L. Recall that light response is logarithmic - a 2x change in Lumens makes a percept ible change in light intensity - a 10% change does not.
Batteries - I love NiMH AA/AAAs - good secondary cells - and my LaCrosse BC-900 programmable charger - but my flashlights run on Lithium primary cells - CR123s. Dependable and inexpensive - 12/$21 from Surefire. With all of my lights now, I finally finished the first three boxes I bought 2/08 last month. YMMV - I just want my light to work when I need it.
Christmas brought another goodie - an Olight M21 Warrior. Rated at 500L on high - most say it is 350L. It's a larger spot with more spill than the E2DL - maybe slightly brighter - but it's close. After high, it has 'high-strobe' - now that is irritating. The Fenix P2D also will blink out SOS on regular high - and will blink fast on turbo. You click through the power levels with the Surefires - high first. The P2D starts with low. The M21 needs to be twisted back and forth at the head, which has heat sink fins, to change power levels - low first.
All in all, the two Surefires - and CR123s, are my choice for EDC - 90% of the time, it's the E1B. I think they list for about the same - real world discounts, like LEO discounts, make them about what the M21 runs, so shop around.
Sorry I am late to the party!
Stainz (Actually, another John!)