It would also have been interesting if they had an M2 as speaker choice number 3.
A/B testing with an M2 or similar speaker vs a larger speaker is hard because the first thing you notice is the different degrees of bass extension. Maybe others have more disciplined ears but I have a tough time getting past that and focusing on the other issues.
With a sub, of course, it's a different story. I held a few impromptu A/B tests with a group of friends, comparing M60s vs M2s, both running "small" with a big-ass sub. At moderate listening levels the differences were remarkably small, although for HT applications the ability to crank up the M60s to higher SPLs while maintaining clarity made a huge difference.
