I think that the only drawback between the Axiom and the HSU is probably the extra $250...on paper they seem to have very similar capabilities. The one bonus of the Axiom is the fit and finish of the product...it'll definitely look more "refined" that the HSU offering. I also like the aluminum cone woofer used in the Axiom...not that there's anything wrong with the carbon fiber reinforced paper of the HSU, I just think that the big silver cone looks better
.
If the Axiom works better for you in terms of size and you can stretch the budget accordingly then I say go with the Axiom...they should be on par with each other (judging from specs alone that is).