I have the smaller brother of that sub, and have listened to the SW700 and SW300. They are more or less similar in regards to the high tuning they have. My room is MUCH smaller than yours and the single SW500 cannot fill it or reach deep enough. Don't believe the frequency response reported. I was not happy so I joined this site to look for alternatives, and now I have settled on making a DIY subwoofer (well subwoofers).
IMO, the SW700 looks nice, but you will get the upgrade bug very soon after.
TL;DR: Not worth the money as a decent movie sub. Spend a little more to get something 10 times better.