Just beware. I have an APC of a similar size. Probably not quite as nice but last time I replaced the batteries, it still said it had plenty left but couldn't sustain my server when I pulled the plug.
+1, I was about to say the same. I am using 3000VA APC units and I replace batteries in their 5th year because I learned to do so the hard way, no matter how good they report themselves to be.
It's best to use them every 6-12 months for a few minutes and check how fast their charge goes down.
There is no feeling like standing in a very dark server room and whispering to yourselves "Hmmm, they should hold for about an hour and we're only out of power for 10s now".
At least the batteries are hot-swappable and I can keep the days counting on those systems with >2000 days of uptime (yeah, I am an old, sick f*ck, but I am proud of that).