The Klipsch subs with numbers like 112SW or 115SW are good designs. Their model with numbers like 12SW or 15SW are the type of sub that has given Klipsch a fairly poor reputation for subwoofers.
Brent Butterworth did a pretty good review (with measurements) of the Klipsch R-115SW for HomeTheaterReview:
Brent Butterworth reviews Klipsch's $899 R-115SW subwoofer, a ported design that uses a 15-inch Cerametallic driver and an 800-watt Class D amplifier.
hometheaterreview.com
If you have found a good deal on one of these, it is a good subwoofer!