I use a CyberPower CP1500AVRLCD to run 2 M200's simultaneously.
Once heated and running they would run for a ~20 minute outage.
Have saved me a couple of times for quick power blips which are long enough to interupt and fail a build.
Unrelated to the UPS - I too was/am concerned about fire hazard so I built a chamber above it with a particulate sensor to detect smoke and a relay drive outlet strip. In the event it detected a higher then normal particulate count ~ >50,000 counts in my case it would cut power and send me a text message. Then I could log on and check the camera. If that was not enough my Halon fire suppression would kick in in the event there was a true fire.
I can text it to shut off or alert me as well. It works really well, I need to run lights out and be safe. I did have to shut it down via text due to a failed build but this was once in about 125 builds.