I have the Klipsch KSW-10 and I must say it pounds really well. It is very controlled and deep for its size. I love this unit as it is very well built. All Klipsch subs are as the people above me are attesting. Next year I plan to move up to my final sub which is a Klipsch KSW-15. I have auditioned it and it is superb. It is not quite at the level of Curtis's RSW-15 which a beast of a unit but nonetheless it is first rate quality. The smaller 10 inchers have the same quality as their larger brothers.
I have a KSW-10 in my 2 channel system and it pounds really well. It's much better now that it is in the living room with a wood floor and sub floor as it was in the theater with concrete sub floors. The Shiva doesn't care about the concrete though, it just flat out pounds
I really can't say they are better than any other sub only becaues I have not heard any other sub. But I have both a RSW-12 and a RSW-15. And oh man, they have a great sound, and good punch. I have an aquantance who came over, he used to be an installer for someone and heard other subs. He was really impressed too.