I am building my HT set-up now and was having a hard time deciding between the HSU os SVS subs so I called Axiom and the technician who I spoke with told me that they had tested both brands and the SVS was better sounding than the HSU. I wholeheartedly trust the info I get from the Axiom folks because they honestly want to help you get the best sound and deal for your $$ even if it costs them sales.
Therefore I'm going with the SVS PB1-ISD ($651.25 shipped to my door)
Thanks again Axiom
Mac

I feel more like I do now than when I got here! :-)