First, these things are gigantic. Shipping weight is 135lbs! I ordered two, one had some firmware issues, but APC was good and send me a replacement unit with little hassle. Otherwise I'm happy with the units. They can power my two big Dell Server (with quad xeons, raid, etc) for a little more than an hour. The software that came with my unit wasn't the newest. Do yourself a favor and download the newest one from APC. Its 100x better.