This is a great stable rackmount battery backup with dual-conversion so devices plugged in always get clean power even with a dirty utility.I never did get the built-in USB or serial management interface to work with any open source monitoring tool, so I had to spring for the add-in SNMP card in order to monitor/manage the UPS. With the add-in card, NetAgent web and SNMP work great.I've had the system up and running for 150 days, including several brief power outages, and haven't even had to think about the system, it just works.