Battery life on the newer models is sufficient and I do like the XPS version but they need to invest in better technology. I read on M4carbine yesterday a guy had 2 of them get real dim while he and his wife were shooting. Took a break and ate lunch and they started working right again. A few other guys chimed in with the same problem.
It's a shame they can't trace the problem down and fix it for good. If they got the reliability issue fixed, they'd corner the market.
