I have not heard any of the subs you are looking at, but the consensus around the forum is that HSU and SVS make better bang for your buck subwoofers, however, Axiom subs are no slouches. To me, I would probably go with either the Axiom EP350 or the SVS PB1-ISD (http://www.svsubwoofers.com/subs_pb1_isd_colors.htm) in a custom color. The reason being that I would not prefer a black subwoofer because a lot of my furniture in my apartment and my speakers consist of maple and silver. A black sub is not preferable for me.
Do not fear in ordering an Axiom sub, they are still great subs for the money, just not quite as great as SVS and HSU. And if finish color is important, getting a matching finish is best with Axiom.
