Note that a pair of Aperion 633Ts are $300 less than M80s. And a pair of M80s have 6 more drivers.
I think the difference may be in the fact that Aperion uses 1" HDF as opposed to 3/4" MDF and what they call "furniture grade" finish. Make no mistake about it...the vinyl finish on the Axioms looks like it is furniture grade.
As for HDF vs. MDF, HDF is denser but not necessarily better. The denser and thicker the wood, the more bracing that is required. This could lead to a higher cabinet resonant frequency and hence a louder resonance. MDF and a moderate amount of bracing is certainly a more elegant and less expensive solution. HDF is also not easy to find and it is harder to work with and hence it is more expensive over-all. Using MDF allows a speaker company to put more money into drivers and quality cross-overs.
All of this may be academic however. Let your ears decide.
