People with more insight on this will ask you for room size, etc for more information about your room and so forth. In my case, I have a lot of air volume to fill, but my room front-to-back is only 12 feet, so it was pointless for me to go anything more than 5.1. I would need a deeper room, and then the debate would be on the "it is worth it" part. From what many people (not all) said, going above 5.1 in many cases is not worth the cost and config. I don't remember why for each of the cases, but many just said that they didn't notice much of an increase in the sound field sounding more "enveloping." To me, I thought that it would, but again, I am at 5.1, so I can not speak personally to it, and I am just relating my research results from about 6 months ago.
Good luck, and if you do get Axiom surrounds, you will wonder why you ever put up with your Polks for so long.
