bhull, I don't think you can go wrong with either choice,I own the Aperion 532's that I use as rears in my 7.1 setup. Aperion makes a fine speaker as does Axiom, what made me decide to go with Axioms over Aperions was I simply compared the amount of awards and praise for both lines as well as the dedicated following of it's owners on both forums.
Those two things alone were enough to sell me on Axiom, and I certainly will never regret my decision.

A computer once beat me at chess, but it was no match for me at kick boxing.