OK, let's try this again. No doubt I will be unable to recapture the spontaneous eloquence of my first post, but perhaps I can be more succinct
I have not heard the M60's, but I have RS750's (and RS300's, RS150's, and the RSC200)as well as M22's and M3's. There are differences between these speakers but I don't find them as dramatic as some of the rhetoric would have it. The Axiom's could be described as comparatively "bright", but I think a lot of this is source-dependent as well.
My upstairs system consists of an average Sony CD player fed through an Audiosource Amp 2 to the M22's. This system can definitely reveal some of the harshness typical of a digital source. I'll soon have a Foreplay (tube) pre-amp sitting between the CD and Amp, which I suspect will smooth this out.
Downstairs in the recording studio, I have M3's fed by an Echo MIA (professional sound card) through a Behringer mixer into a Carver receiver, and they sound very neutral. Carver is often referred to as having a "warm" sound, so perhaps this is a factor. The MIA puts out a +4 signal, so it is very hot and sensitive to small changes.
The Rockets are in the HT, fed by a Denon 2200 into an Outlaw 950 and 7 Outlaw (200w, more like 300w into the 6 Ohm 750's)monoblocks. This system blows away anyone who hears it, as it should given the relative cost.
I would place the 750's at the head of the class, but they are also the most expensive. One major factor is that I find the 750's less fatiguing for long periods of high-volume listening. On a non-sonic note, the Axiom finishes can't really compete with the Rockets, but this was never a deal-killer- the Axiom's in Beech go better with the living room than the Rocket finishes would, and vice-versa in the HT.
I am happy with all my systems, and am not really itching to change anything (except maybe swapping out the Amp 2 for a couple of Bottlehead Paramours)
Comparing on price alone, I would give the edge to the M22's over the RS150's. They are more revealing and detailed. The M3's are just a tremendous bargain, all comparisons aside. The 750's are in a different class though- I'd really like to hear the M60's or M80's in comparison. For the record, I've never understood the "muffled", or "25th row" comments about Rockets- I just don't hear it.
I think Axiom and Onix are both great, and look forward to a long association with both. So ultimately this is just a long-winded way of saying: "Ya gotta hear them for yourself!"