Hi Joe,
My Aperion Speakers:
2) 632 L/R, 2) 532 L/R, 1) 532 C, 2) 534-SS, 2) 422 rear surrounds and an S-10 Sub.
Both the Aperion 532 and Axiom M2 are rear ported. They will both need a bit of room to breathe at the rear of the speaker since it sounds you may be installing them in bookcases. I have one of my front 532’s mounted in a freestanding bookcase and needed to cut a hole in the back that aligned with the port to reduce vibration and a somewhat muddied sound at lower frequencies.
The 532 uses a silk dome tweeter where the M2 uses a titanium metal dome tweeter. I have read that metal dome tweeters can sound harsh, but I have not heard Axiom.
The 532’s are real wood with immaculate fit and finish. To get real wood in the M2’s would cost about $70 more per pair than the 532’s.
I would highly recommend the 534’s for side surround if you can wall mount them. IMO they will blend better with the room’s décor than a box speaker due to their shape and they do sound great in 5.1 multi-channel from my DVD and other sound fields.
Jack