Where does he say paper cones are inferior (or as other users here have posted, "crap")?
The cone is paper, and the edge a relatively large diameter half roll foam surround, pretty standard stuff for inexpensive loudspeakers. Frankly, for a subwoofer, as long as the cone won't break from the stress of forces, anything commonly used if made of a sufficient thickness (which for different materials means a different mass of course) is going to be pistonic, a term meaning it will act like an air pump, and simply push and pull the air alternately setting up those low frequency waves we enjoy so much. Even paper is hard enough to be acting like a simple piston (what you want) at subwoofer frequencies. This of course raises the question, why use aluminum or polypropylene or something exotic? Well, if the aluminum is coupled to the voice coil by a thermally conductive bobbin, that will add lots of heat sinking. Paper just burns if you get it too hot. Polypropylene will either melt, or come unglued. Of course, paper lacks sex appeal, and sometimes that is what marketing asks for. If it is new, it must be better right? The foam surround is plenty wide enough to not mechanically limit the travel of the woofer, and given the relatively high cutoff in this box, a reasonably large one occupying more than 5 cubic feet, unless you start putting 1400 watts of power in at 20 Hz with both ports open, I doubt this woofer will strain. Listening tests (read further) confirm.
Generally paper cones are less expensive than most other material (with some exceptions, e.g., see SEAS). However, most know for low frequency response in particular, cone material doesn't sound any different from any other material. So as long as the driver has the ability to handle the amount of power you're throwing at it, paper is a good compromise to keep costs down.
Where does he say that BASH is "crap"?
Actually, I was quite surprised to find the amp used with the Hsu was a BASH design. I will admit my bias against the company, yet I found it had the ability to drive the Hsu sub to considerable volume levels in a very large room. My experience in the past with BASH amps, has been less than encouraging, but I have no negative comments to make about the finesse and skill which was used to adjust the maximum output of this amp so that there were no hard clipping or compression artifacts audible enough to make me complain.
I was not expecting too much from the BASH amplifier, but despite that, I found it performed well, and more importantly I found Hsu's approach to his system design with limited power preferable to a GO DOWN TO 20 Hz at all costs approach, and to hell with the sensitivity. The VTF-15H was clearly a well compromised effort based on maximum performance for the dollar.
He does mention the "potentiometer action felt rather soft or loose". Which is one of the things BASH gets dinged for regularly (i.e., QC). The first BASH amp on my PB13 was faulty, the second one had a sticky frequency/x-over knob, the third one was fine. BASH amps cost less for a reason. However, for the most part they are a great compromise when looking to cut costs and used by a large number of vendors. Most "amp" purists do not like them at all, and it is evident the reviewer had a bias against them but seemed to not be able to complain about its performance (meaning it was a well designed sub).
One area he does touch on with the amp is the low pass ...
My biggest criticism of the amplifier was the fact that we are only given a very limited range of Low Pass frequencies to use. (30 - 90 Hz)
I agree, it is odd that it was only 30 to 90hz (I've never seen one so small). Though in reality, who cares given most of us disable it and use the bass management from our receivers (as the reviewer indicates), and this is nitpicking especially since the sub gives the user the ability to disable it (I think?). Some subs don't even bother with this (E.g., SVS PB10, or Funky Waves new plate amp). Why? Cost savings.