Welcome to the forum!
I never heard the Aperions and obviously, as an Axiom owner, I don't find them fatiguing or else I would have returned them. I would consider Axiom speaker to be forward as forwardness is often related to detailed mids but not harsh or irritating. I have heard both M60s and M80s and the M80s is the most "forward" of the 2.
My room is similar to yours, 20x11ft, hardwood, no curtains. At very high volumes, the sound starts to become "blurry", not from the brightness but from the reflections in the room, so the more acoustically friendly your room would be, the better they would sound but this is true for any accurate speaker IMO. For example, my M80s sounded better when I had carpet, still sounds good with a thick pile rug but it becomes horrible with hardwood and an empty room because of the echo.
You can do a few things
1) go to the "hearing things" forum and see if you can audition Axiom speakers near you.
2) Where do you live in Canada? If in the GTA, you could always go to the Axiom facility, listen there and get a factory tour.
3) You could order them, listen at your place and return them if you don't like them.