I own over 20 different models of LED flashlights easily available from local retail stores and accepting common AA, C or D cell batteries.  In my reviews I will group each type separately and compare simular models with each other.

This review is for the FENIX Everyday E21 2AA LED Flashlight which takes two AA batteries and is rated at 154 lumens, and has a drop-proof and waterproof rating.  Other 2AA 100+ lumen class flashlights I own are the Norlite 08-NSWAT 2AA Tactical LED Flashlight and the Energizer Ultimate Lithium 1 LED 2AA Hand Held Flashlight.  All have lifetime warranties.

The Fenix, Norlite and Energizer are roughly the same size.  All accept standard easy-to-find AA batteries (which is an important feature for me).

Pros:

Why is the Fenix E21 LED Flashlight the best?  It is the only one of this set that has ZERO battery shake.  There is no battery rattle and it creates complete confidence held in the hand.  The Fenix E21 LED Flashlight is the brightest of this lot.  Although the beam is not adjustable -- there is no focus twist -- the center spot is brighter than the Norlite and the Energizer no matter how they are pointed.

All three flashlight models have rear cap press-on buttons.  The Fenix E21 LED Flashlight rear button has the strongest feel.  Also, the Fenix is the only one having temporary quick-shine by half-pressing the rear cap button without making it click on.  Neither the Norlite 08-NSWAT 2AA Tactical LED Flashlight or the Energizer Ultimate Lithium 1 LED 2AA Hand Held Flashlight have that ability.

The Fenix has a 33% brightness map reading mode.  The idea behind this is worthy because an intense spot light does not make for a good map reading light, however, the Fenix still has a small focused center spot.  There are much better LED flashlights for map reading in the sub-100 luman class.  But within the over 100 lumen class of flashlights I compare here, the Energizer Ultimate also has a map reading low energy mode.  The Norelite 08-NSWAT flashlight does not have a map reading mode.

Cons:

The Fenix E21 LED Flashlight does not have a built-in belt clip.  Neither does the Norlite, but the Energizer Ultimate does.  The Fenix cannot be adjusted into a flood beam.  Neither can the Norlite or the Energizer Ultimate.

The Fenix E21 LED Flashlight cannot be set on end -- say set on a desk pointing to the ceiling -- like the Duracell Daylite flashlights can.  Of the 2AA 100+ lumen class set, only the Energizer Ultimate Lithium 1 LED 2AA Hand Held Flashlight can be set on end (although it would be tippy).

If laid down on a flat surface, there is nothing to stop the Fenix E21 LED Flashlight from rolling away.  However, the Norlite has a notched ring around the grip to prevent rolling.  With the Energizer Ultimate, the belt clip can be used to prevent rolling.

The final small negative is with exterior gripping.  The Fenix E21 LED Flashlight and the Norlite 08-NSWAT Tactical Flashlight have textured aluminum, while the Energizer Ultimate has a rubberized exterior.  In the world of textured aluminum exterior flashlights, there is better gripping textured aluminum.  Neither of these 100+ lumen class LED flashlights has a biting grip texture as good as the simple sub-100 lumen class Cabela's Model IK-517128 1/2 Watt 2AA LED Flashlight, for example.  Nothing is perfect.

Recommended: Yes