I own a SVS PC-Ultra, and am quite happy with it. It's clean, blends well with my mains, and comes with a PEQ that helps take out the worst bass "hump" in your room. I also like the ability to be able to tune the sub with the foam plugs. The 16Hz (i.e. one foam plug) tune sounds better for music, but the 20Hz tune (no plugs) is better for movies. I haven't tried the 12Hz tune yet... that seems to be guilding the lilly, so to speak, though I'll no doubt try it sooner or later.
If I was going to spend $3K+ on a subwoofer, though, I'd give serious consideration to the Thiel line of subwoofers, JL Audio's Fathom, and the Velodyne digital drive series subs.
If I was going to spend $3K+ on a subwoofer, though, I'd give serious consideration to the Thiel line of subwoofers, JL Audio's Fathom, and the Velodyne digital drive series subs.