Don't wait till you have a power glitch to find out its really defective.

At night, a small power glitch will sound the alarm and wake me up

It keeps my wireless access point running when I unplug the UPS from the wall, so it's probably good during an extended power outage, but both times we recently had a brief power glitch during storms, the access point still rebooted, so I'm not sure why the UPS didn't keep it running stably.