Paul,
First comments on the new SVS 10". It's physically larger than the HSU so there is more volume in the unit. It's deeper and louder at lower levels and I think it has a fuller sound. It enhances my music and I can feel this one much more than I did the HSU. The HSU was a great sub but I believe this SVS is a better, more powerful sub. Now I'm thinking upgrade!! Yipes...