Grexx,
The Klipsch you mention was one of the speakers I auditioned before ordering my M60s (not the M80s compare you are seeking). I can give you input based on that.
"Tinny" is a close approximation of what the Klipsch sounded like to me, but sharp / harsh / too vivid would need to be combined with that to provide a complete description. Beyond "bright".
In researching the Axioms, I was concerned when I saw the word "bright" used to describe them a few times. After ordering, setting up and breaking in, the Axioms are clearly not bright. Rather works like transparent, clear, concise, full come to mind.
This area is very subjective, and your ears will be the ultimate decision drivers. But the Klipsch is like someone waving a finger in your face while the Axioms are more like having your ears caressed.
I hope this is helpful; it is very difficult to describe a concept like bright or tinny.
