I never heard the HSU or the SVS, but I love my single EP500 which supplies way more then enough quality bottem end for my 450 square foot dedicated HT room. It also has the DSP chip which I think is worth a few extra dollars.

paul

paul

Axiom M80, VP180, Qs8, EP500
Epson 3020
Rotel RB-880
Denon AVR-990