Firstly, to address all of the DIY guys: Sure, you should, theoretically, always be able to build it yourself for cheaper. Hell, I could have built my house, my car, all of my furniture, etc..., etc..., etc..., for cheaper than what I bought it all for. But that's not really the point when someone asks for a consumer (for lack of a better term) sub recommendation, now is it? I don't know about you guys but when I ask for a speaker recommendation I don't want to hear "build it yourself," I want to hear honest recommendations about which speaker to buy and why. I'm not interested in building it myself or I would have, right? If I wanted an enclosure recommendation, a woofer recommendation, an amp recommendation, etc..., I would ask for one.
Now, to address the OP: I don't really know why the HSU gets no love. I have one and I absolutely love it. Would gladly recommend it to my friends. I'll also be the first to say that yes, it was a bit pricey and yes, there are probably others for that price that will perform as well as the HSU (maybe even better), but they weren't around or available for a demo when I was searching. I'm entirely satisfied with it, even though I payed a few hundred more than it's going for right now.
After reading the other responses, it would seem that basically everyone feels you should just build one or buy one of the few others that can compete. That makes sense, but if you were to ask me, or I actually hung around to see the recommendation requests, I would surely recommend the HSU. I also agree with a few others as well that sheer numbers don't mean everything. What I care about is how it actually performs and sounds, not what's written on paper. Sure, the numbers can be good selling points and performance indicators, but I actually demoed MANY subs and found this baby to be about the best bang for my buck out of what I demoed (which obviously couldn't be every sub out there).
In closing, I definitely feel the HSU should get a bit more love and recommendations, but it seems everyone here just wants to pinch pennies and complain about cost. That's cool, the economy sucks anyways...