I debated long and hard about my choice of subwoofer for my own personal use. I needed something to follow in the foot steps of Ken Kreisel's DXD12012 - a dual 12" push/pull sealed sub, with around 3,000 watts behind it. I needed something small (SB13 was too big), something that wouldn't seem slow after owning the above, and certainly sound clean like the KKs. Other than KEF's R400b and B&W DB1, I was considering the SB1000 from a price point of view, which size wise was perfect. I just felt that if I was going to go for a sub with a 12" driver, I may as well go for the SB2000, even if it had more power than I needed as it's this power that is going to help with the depth too. I never really watch any films any higher than around -20dB on my pre (other than quiet films like Zodiac), so didn't need all out power, and I reckon I've barely used half of what the SB2000 is capable of. But as I say, I chose the SB2000 for other qualities it has. Even my playback levels would be fine for a BK, and probably numerous speaker manufacturer's subs, but I want clean output, as well as some good presence and depth, which the SB2000 has never failed to deliver. I watched Super 8 last night, and despite having this sub for a year and a half, it impressed me with its speed, particularly with the very low notes in Super 8 - you could hear deep bass notes suddenly stopping, there was no smearing or looseness to the sub bass at all. Highly impressive.
All subs will be compromised in one way or another, whether lacking depth due to size, or ultimate output etc, but the SB2000 doesn't feel in any way compromised for its size or price - if anything it feels like it delivers more than it should do for its size and price.