I had some Polk bookshelf speakers before my M80s. They were okay, but I just thought there should be more of something in the sound. When I first got my M80s, I wasn't wowed. At first I thought it was just that my receiver was underpowered, which may have contributed, but it wasn't until I spent some real time listening to them that I loved them. There's a lot more presence, especially with movies and music with a high dynamic range. They feel... big. The major events in movies now feel like major events. To be fair, some of this is handled by my EP800s now, as well as my ButtKicker, but even without them running, the M80s do quite well on their own.
I look forward to when Axiom has a new flagship speaker that I can put through its paces. Of course, I may become impatient at some point, simply upgrading from my v2s to v3s so I can give these to my dad and have him pass his Polks on to a friend of mine. We'll see!