Bests & Worsts Reviews from Amazon

I bought a bunch of these after reading reviews for many detectors. There doesn't seem to be a detector out there without complaints that they don't work. Sure enough, these sound an alarm periodically and then stop on their own. I have no idea if they actually work. The fact that they randomly alarm and then stop without explanation make me nervous. I'd replace them, but since every detector has bad reviews, I don't know what to replace them with. Updated Nov 2015: Continuing to have issues with false alarms. I wonder if any of them actually work... Updated March 2016: I had to wait on hold for 38 minutes, but once I got through, they are mailing me a replacement detector for the one that keeps going off, without charging me shipping or requiring me to ship back the old one. Much happier. I hope these really work. Updated Sept 2016: Another one failed. This one started chirping in a way that (according to the label on the alarm) indicates that the alarm has reached the end of its 10-year life. The manufacturing date on the alarm is May, 2015, so the alarm is only 18 months old. Updated Sept 2019: 2 more failed -- dead batteries. 4 failures on 6 of these (some bought at OSH) in less than 3 years. Changed my review to a 1 star instead of 2.