I've had the SB12-NSD hooked up and playing for about 8 of listening. I really didn't want to like this sub, once I first hooked it up as its replacement had been. But now that things are dialed in a bit better, this little dynamo is really impressing me. Coming from the Polk 505, the SVS sub really illustrates how much good-sounding bass I was missing. I am still working to make sure I give this sub a fair chance to convince me to keep it. Those who said I'd likely not get the thump I crave were right, but I have to admit that its growing on me. though it doesn't seem to have that sense of "pressurization" that gives the feeling of being at a live show, particularly the kick-drums. The 505 excelled at that, and it did have a lot of output even at low volume.
For gaming, the SB12 is a phenom. Mini-nukes in Fallout 3 gave me all the rumbling I needed, and sounded much more impactful than the 505, if that makes any sense. Going to go hear it in other games.
i7-2600k @4.4ghz/gtx 780(stock clocks)/Samsung 830 @256gb/WD Veloc. 1TB/Sound via Sony 7.1ch cheapo/B&W 601se/KEF C-40(dual-8"driver mini-towers)/(arriving soon)SVS PB-1000 sub/FiiO E17 Alpen DAC/Audio Technica M50 headphones(never used! heheh)/Crossover 2560x1440 monitor