You can safely expect a far superior sound to the Klipsh from Axiom. They're not bright; they're just accurate. Therefore, if the recording is hot, they can be perceived as bright. Haven't heard the Athenas, but the Axioms are excellent.

BTW, bi-wiring is a myth. Have a look at this article.

The receiver warmth/brightness thing is highly debatable. You will hear both sides of the issue around here.

I am the Doctor, and THIS... is my SPOON!