Hi Alex,

I have never really liked the micro keychain lights powered by 2016 lithium cells due to the cost of long term ownership and their poor overall performance.

It terms of ergonomics, weight and usefulness both the LRI Xlight and the Freedom Micro are actually poor performers compared to other solutions. Although the Xlight is 3 times brighter using a very good Nichia LED the battery time I suspect would be just over an hours use compared to the Freedom Micro 3 hours use.
Taking into account the 2016 battery costs also compared to a rechargeable AAA Eneloop cell for example. 1 hours use for X-light is going to cost $2.00 (assuming each 2016 cell costs $1.00 each).

I personally would use a Fenix LOD CE flashlight with an Eneloop AAA cell or lithium AAA cell both on a keychain or even in a small tobacco tin type PSK, just because of the extraordinary performance no matter the cost of initial ownership (though the long term costs of ownership are actually less after say about 20-25 hours use when compared to the 2016 powered X-light). The Fenix flashlight weighs in at just over the oz mark (with a Lithium AAA cell) and is just slightly larger, its performance is just nothing short of amazing being brighter than a 3D Maglite for 1 hr NiMh (1.5 hrs with a Lithium AAA), and more light output than a 2D maglite for more than 3 hrs NiMh (4hrs with a lithium AAA). On its lowest power setting it will last more than 8 hrs at the same light output as the X-light making it more than 3 times more efficient if overall weight differences are accounted for. Also in an emergency replacement cells are much more readily available than the 2016 cells. Although the initial cost of ownership is around $45 for the Fenix it makes much more sense in the long term than any 2016 powered light. 2016 powered lights may be useful for certain tasks but when the chips are down I would rather have the flexibility of the Fenix LOD CE.