That's a good sub for a small to medium sized room. It won't have the output of an SB12, however the finish is *much* nicer in my opinion. In a small room, they'll do about the same as an SVS or Hsu, in a bigger room, you'd be better off with the SVS or Hsu.
It will be a *lot* better than your Sony sub, either way. Like 10x better...
Looks like the UFW's are all gone, but they have 500-watt ULW's left (the only difference is the lacquer top isn't there) for $279 (black) and $299 (rosewood). Two of these would do very very well i would think, even in a room on the larger side.