It's really impossible to say how the NAD, Cambridge, Sony and Yammie compare to each other sound-wise with M3s until one has had a chance to audition them. I don't see much difference between these on paper but not much info is given to begin with. From an internal build perspective, I'd take the NAD or Cambridge with preference for the Cambridge, but that doesn't mean they sound better than the others. I can't see how spending more for the NAD or Cambridge would buy you better sound.

House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated