I guess the term "laid back" means different things to different people. I used to own a set of Sony 3-way towers. To me, they were very heavy in the mid-range...very unnatural. The highs were also not very clear...they seemed to strain to reproduce the sound. They were "intense" sounding...to me. They tried too hard, and came up short.
So when I say my M40's are "laid back", I mean that they reproduce the sound effortlessly. Clean, clear and concise. They don't seem to boost the sound spectrum at any point.
That said, they are a 2-way design, which leads me to believe that the mid-range is not as apparent as the other 3-way Axioms. In that way, I believe they are "laid back"...less "in-your-face". Again, that is just my opinion.
I'll have to be honest, the M40's were a BIG surprise. The bass is extremely smooth, although not super-deep. But certainly deep enough for most rock music. (You'll want a nice sub for movies)
I've also heard Paradigms and PSB (only heard Energy's in stores). Both really good speakers. It was a toss-up between the 3 brands. All 3 had similar stats, all had good reviews. But I choose Axiom, and am not disappointed in the least.