The M91 is not regulated on 2 primaries. To get full, regulated output in a two cell host, you will need to run lithium ions, effectively halving your capacity. Right?
Good point GeoBruin, and definitely. I was, actually, thinking LIon when I made that statement... you would need 3 primaries to run in regulation with the M91. A better statement by me would have been that multiple cells are still needed for regulated runtime with either light... If the SHO could run at that level on 1 LIon like the M61, well then, that would be a game changer!!
Also, I agree with Bill, get that output in the hound dog with the smaller die and then you'll have something as well...
But until then, I really do still feel it comes down to beam preference given the current P60 format... adding that, true (and a point I clearly overlooked), the option to run on 2 primaries in regulation is a nice to have if you're not charging your own, but not enought justify the extra spend if you are.
And, by the way, my stance is not that it's not a great offering, I think it is... just not different enough to justify the spend given that I already have about 20 Malkoff drop-ins with three being M91's. For someone buying their first, or second, or even third.. I think it's a lot to consider.