I didn't know about using to 2 subs which is ideal; however, in case you missed my reply over at AVS, here it is:
GTP's assessments are correct. From what I read from the gurus on the net, vertical speakers normally shouldn't be laid down if you can help it especially if there are more than 2 drivers in each enclosure.
I have 3 sets - 2 separate audio only systems (M2s + EP-400 sub; M3s only) & a HT ( M22s each perched on its own Velodyne sub).
The M2s are small bookshelfs that are really intended to be used with a sub for fuller sound & are more than satisfying in that type of array - I am most impressed with mine - big sound with small footprint.
M22s sound similar to the M2s as they have the same drivers. They are are good on their own but shine with a sub.
The M3 has the same tweeter but bigger woofer. It therefore sounds similar but also a little different (if that makes any sense).; however, for normal music listening, it doesn't really need a sub as it has a bit of mid bass bump to give the impression of more bass. This actually works quite well, not quite as accurate as the M2 series but still pleasing to listen to.
If your room isn't too large, I'd recommend the M2s with 2 subs & M2 center (if you could use it vertically). I don't have an Axiom center so I can't help you there.
If a sub is not involved, then the M3s would be a better way to go.
Overall the M22s would be best due to higher power handling, but I hear ya when it comes to WAF.
Unfortunately aesthetics are often large problems that need to be overcome. System appearance is very important to me as well...