It depends - it's performance is not bad and can be a good value if you can get it for $500, BUT at it's MAP of $899 there are better options for sure. HSU VTF-3mk5, Reaction Audio, PSA and new Rythmic FVX15 sub.
You got to understand something here: The DIY Kit I linked above and you could build it around $500 will closely compete with these 900-1000 commercial offerings.
Review:
http://hometheaterreview.com/klipsch-r-115sw-subwoofer-reviewed/?page=2
Maximum output
CEA-2010
(2M RMS)
63 Hz 114.3 dB L
50 Hz 115.7 dB L
40 Hz 112.4 dB L
31.5 Hz 109.6 dB L
25 Hz 104.8 dB
20 Hz 99.7 dB
To rephrase a words from BOC song don't fear the BASH. This specific amp design doesn't necessarily makes HSU amps less reliable. HSU sells thousands of subs, and I yet to hear any noticeable mentions with their amps.
Dr HSU is very talented, not bs engineer and he knows how to build great products at decent price and he's been doing it for quite a while now.