RAID is not a replacement for a backup! Here's why.
Is there a list of supported UPS units for the Quad? I have a Belkin UPS with a USB port that I usually attach to my PC but not want to use with my quad but can't seem to see it when it's plugged into the rear USB port even after a reboot....
APC's SmartUPS line of UPSs will work fine.
The APC Back UPS range also work. I have a Back-UPS BK650-AS and it works fine. I think APC UPS with USB will work. Be sure not to get a APC UPS that uses a serial port to communicate.