APC ES 550G UPS
I installed the APC ES 550G UPS to my Linux Mint 13 desktop. I got the 'apcupsd' package via the repository and had it all up and running within a half hour. Get the 'apcupsd', 'apcupsd-cgi' and the 'apcupsd-doc' packages via apt-get or synaptic.
Then edit the '/etc/apcupsd/apcupsd.conf' file. Change 'UPSCABLE' to 'usb' and 'UPSTYPE' to 'usb'. You can change times etc. if you want but it is not necessary to get things going. Look at the rest of the stuff in '/etc/apcupsd' just to get an idea how everything works. You might want to comment out the 'FIELD UPSTEMP' 'UPS Temp' in 'multimon.conf' as this device does not seem to support temperature.
You will also need to edit the '/etc/default/apcupsd' and change 'ISCONFIGURED=no' to 'yes'. Then you can start the daemon by 'sudo invoke-rc.d apcupsd start' (or 'sudo /etc/init.d/apcupsd start'). You can use your browser to check the status by going to 'http://localhost/cgi-bin/apcusbd/multimon.cgi'.
I have my computer and my wireless router plugged into the UPS. I tested it out by pulling the UPS plug and sure enough the power stayed up and the power outage was logged in my 'syslog', an email was sent to 'root' and the 'multimon.cgi' reported the outage. I plugged the UPS back in and the event was logged on all three: 'email', 'syslog' and 'multimon.cgi'.
All in all the APC UPS seems to work just fine. The status log, '/var/log/apcupsd.status', shows an UPS load of only 26% and predicts 27 minutes of UPS power. With only 26% load I may plug my phone answering machine in to the UPS also so I don't have to reset the clock every time we have a brown-out.
For $59.99 from Amazon.com this seems like a perfect fit for my home system. I understand that APC has software for Window$ if you really want to punish yourself. As always APC like most vendors could mention that the UPS works just fine on Linux and point people to the 'apcupsd' packages. But maybe APC is afraid of alienating Microsoft or maybe they just figure if someone is smart enough to use Linux they are probably smart enough to figure everything out for themselves.