The SB-1000 is a good option as well, however being sealed means it's output is lower, especially down low where movie effects are prevalent. The PB-1000 is still very accurate, and unless you need a small footprint, or are in a small room, I think it's the better all-around choice. The main competitor to the PB-1000 is the Rythmik LV12R. It will have similar extension, but being that is has a bigger driver, it will play louder.
What are your room dimensions? (HxWxD) And is it open to any other spaces? Subs need to pressurize the entire connected volume of a space, so if you are in a big area the Rythmik might be a better choice.
Denon AVR-1713 | EMP E55Ti | EMP E56Ci | EMP E5Bi | BIC F-12