Bob,
I almost sent my M80’s back after I first got them. My first impressions were similar to yours. The first thing I did was throw a rug down in front of them (I have hard wood floors). This made a world of difference. The second thing I did was re-position them to the side and rear walls. The M80’s need to breath. You want them at least 12” away from a back wall and at least that far away from side walls. They were still too bright for me, even though the bass and mid range improved. I called Axiom and they sent me four resisters to try. They go in line with the tweeters. With the resisters installed, all was glorious and I kept them. I have since removed the resisters, but only after I played with Audysey settings.

M80’s are not for everyone. I don’t listen to much Classical or Jazz. I tend to listen to more rock / Alt rock than anything. They sound good to me. They sound horrible with poorly recorded music though….. Make sure you give them a fair try with a disk that you know to be of good quality. Green Day, American Idiot or any of the Trapt disks are good alt rock disk that comes to mind. If those sounds like crap to you after you exhaust room set up suggestions, then I’d send them back.