I have the SVS PC13-Ultra and couldn't be more happier with it. It plays down deep/low and is just an amazing woofer altogether. With that being said though, I have absolutely nothing to compare it to.

Receiver: Yamaha RX-V2200
Main: Axiom m80
CC: Axiom VP150
Surround: Axiom QS8
Sub: SVS PC13-Ultra