I had that sub... for about 1/2 day. While its not unimpressive out of the box, i mean its loud but not as boomy as I thought... Biggest problem is the extension. Once you get below 30hz or so, its performance suffers. After using the crawl test in 3 different rooms, it measured pretty poorly. I think the box was simply modeled for SPL and leaves a lot to be desired for a high quality HT sub. I payed 800 for mine, but would have had a hard time keeping it at 4 knowing what else is available. It might be hard to do a lot better at 4, but if you're willing to spend even just a little bit more, you'll be much happier. There are some nice ID subs available and even some DIY as well. The Niles still seems like a great option.
I really dont like to "bash" a product particularly after somebody owns it and if you like it that's fantastic and really all that matters. I say this only because I'm a pretty big klipsch advocate and give them quite a bit of praise. Their horns are a nice product and decent value. Too bad their subs arent horns. The last "good" sub they made is the RSW15. I havent heard their new Palladium Sub, but even their THX dual 15s were fairly disappointing. Ok, short story long, if its at all possible to maybe get into something different, I'd suggest it. When you start shopping for better LCR's you'll have nightmares trying to integrate that sub.