Mac,
My STF-3 has "only" 300w. But it's set to 9 o'clock on the gain dial in a huge room (22x27xvaulted). I couldn't possibly use all its power. Further, it tracks to 20Hz in-room @-3db. There is more spl than I can legally use in a rural neighborhood.
I've heard such good things about the SVS, that I almost went that route. BUT...the Hsu people gave me GREAT service and personal treatment, have a smaller and less expensive product (that is more than adequate for 99% of possible applications), and by all reports is 'tighter' or more musical than its counterparts. (Even my little STF-1 was wonderful...as will Jaxvon attest, as well.) When I temporarily had two STF-3's running, the depth, power, and crispness of bass was absolutely stunning. One day, I'll be able to afford another.
I know you've seen and heard most of the SVS's. I hope you give yourself the benefit of hearing the others that intrigue you, as well.