Ive had 2 different 12" Klipsch subs, one down firing, and one front firing...
I had those for a while, both offered I'll say good 1 note bass.....
Then I bought a real Sub... SVS, but then again, I went with a dual 12, which put me in an entirely different bracket... But the SVS is in all respects, alot more sensitive, accurate and powerful....
Svs will always trump Klipsch....
If in your position, you are able to stretch your budget a touch, maybe consider the SB-12plus.... They are getting awesome reviews...
Or Don't forget, you get a good bang for your buck with HSU...
Good Luck...