In response to the letter about swapping out devices that use button batteries, I would point out that some EOTech holographic sights use standard AA batteries, that are easily recharged. The EOTech 512 is an example. These sights are robust, easy to use and stay calibrated through heavy use.
Combined with the Sanyo Eneloop AA batteries the EOTech sight would be useful for many years to anyone with a solar battery charger. The Eneloop batteries can be recharged over 1,500 times and unlike other rechargeables, they maintain 75% of their charge after three years of storage. While the EOTech doesn't have the ambient light intake or tritium sights of the mentioned Trijicon, it is an option that folks should explore as they compare options. Just my humble opinion. - Ohio Shawn