I have the ASW-8, and it works almost perfectly for me. Very limited at SPL's above 95 though. And it doesn't work well for me when I set the crossover above 80 Hz.
But- my house is not forgiving towards bass much below about 35 Hz, I don't listen much above 90 Db's and I just needed to extend the lower octave of my speakers. the ASW-8 works fine.
What it boils down to is your situation...
1) Why do you need a sub?
2) What are your listening habits?
3) How large of a room?
4) Shape of room?
5) What are your mains?
5) Any WAF issues?
these and other questions, once answered, can help ster you in the right direction.
I can say that the TSC subs are fine products. Not state-of the-art by any means, but they seem to work as advertised.
-S