Do you prefer a fuller, softer bass sound, or a tighter, harder, yet less full kind of sound?
SVS (from the one I heard, and from reports from a couple of other people) have a softer, yet fuller sound.
Hsu on the other hand has a tighter, punchier sound, but isn't quite as smooth or full sounding.
To use an anaology I've used before, the SVS is like being punched by a guy wearing boxing gloves. A Hsu is like getting hit with bare knuckles. Both hit hard, but are different.
Something to ponder before making the purchase.