I've bought a few photons and other similar coin cell lights and no of them lasted very long, they all eventually die in some way so I stick with AA powered lights.
Haven't worn a watch in years since they catch on everything, be it the inside of the server or brush. Surefire's are nice lights but there are other lights which are just as bright and run from AA's.
The logistics of stocking up make keeping various sizes more difficult, I've been there. You could buy 100 AA's and 100 AAA's and 100 C's and 100 D's and 100 of the others like 9v, cr123, etc or just buy 500 AA's and be done with it.
Rotating stock to keep all those sizes fresh take a lot more work too.
Plus at this point i have at least three sets of AA Eneloops for every piece of gear and items like my GPS will go 16 hours on a set of batteries so I have 3x16 hours of constant use for it before I even need to get into the backup alkalines and thats only if I can't get some of the other sets recharged.
The amount of $ I save bu not having those other sizes had allowed me to buy a lot more rechargeables and a nice charger/analyzer to make sure they run well. I'm at the point where I get longer runtime from an rechargeable than I do a name brand alkaline.