"The M3s seemed to have better balance and a bit more bass impact (which was a little baffling considering the difference in cabinet sizes)."
Then, respectfully, your “shootout” could not have been setup properly as there is no way the M3’s have a more extended bottom end than any of the Axiom towers.
Further, when you setup the speakers, where they all in approximately the same position or in different positions all together? Where the tweeters all at ear level? (albeit, the latter has no bearing on bass response)
I find it amusing, and I write this with a grin, if I were to favourably compare the M60’s or M80’s to exotic European loudspeakers priced at $2500.00 +, most of the people on this forum would have no problem accepting a positive comparison . But if I compare the M50’s to the M60’s/M80’s which are built by the same manufacturer in the same building, using essentially the same drivers, technology and research, people grimace.
Sometimes you just have to laugh!!