I have just gotten an EOTech for my DPMS AR-15 with a flip out x3 magnifier. I love it. Target acquisition, reliability and and accuracy are all excellent. The thing I hate about it is that it requires batteries.
Granted it takes standard AA batteries. That is good. Easier to find after the Killer Robot Uprising begins. My AR even has a special compartment that can store a couple spare AA batteries. But if the batteries are dead, if I get bathed in EMP, or any number of other problems happen, I would be hosed.
On inventory I have ten devices that require batteries. Lots of various kinds.
At the recent Northcoast Blogshoot One of my DOT scopes went dead. Luckily, my CX4 Storm carbine has excellent, spot on, iron sights. I am going to make sure that ALL my sight systems that require batteries also have reliable backup iron sights!
--It's not IF the batteries will fail. It's WHEN will they fail?