What are you hoping to do with this sub? If you are looking for something to just be loud for dance parties or something along those lines I would get the CV if you want nice accurate bass...well I wouldn't look at either of those companies. I am partial to SVS as they make a great woofer and I have heard HSU does as well, but haven't had a chance to hear one yet.
What are the dimensions of your room and your listening habits?