I'm thinking the 6 volt head would be a better choice for most. 55,000 lux and a hour runtime. Longer on a 18650. Make a pretty good backup search/rescue light.
Looking at the specs and runtime, it looks like the E2XT is basically the E2HT in a larger bezel with a larger TIR lens to better focus the beam. It seems the E2XTD is likewise only with direct drive.
The E2HT, E2XT and E2XTD are designed as replacement heads for the Surefire 600 series weapon lights, and is why none of them are listed as turnkey flashlights. The narrow beams with minimal spill are ideally suited for rifles with magnified optics as the FOV through the optic is generally narrow (with the exception of 1x magnification on LPVO scopes). While a wide beam (higher lumens/lower lux) is ideal for short range WML use, the longer throw of these three heads are better suited for engaging targets at longer distances.
Due to the limited spill, I'm not sure any of these heads would work well for S&R use, I think the Hound Dogs are a much better choice for that application.
Beyond WML use, there is not much general-use utility for these heads other than the one I have been speaking of in previous threads - the use of the light to blind an assailant at close range in self-defense applications. In this case, it's the high lux/candela capability of these heads that make them ideal, and the lack of bright spill and short runtimes are of little-to-no consequence.
No doubt these heads are for niche applications. Based on the typical discussions of color temp, beam conformity, runtime, etc. on this board (and forum discussion guidelines), I don't expect there will be much discussion about these particular Malkoff products.
