Dunno... It's a bit tough to answer that, the sound is both similar and quite different at the same time. Similar in that the sound, like all maggies is honest. Different in the portrail though.
The double MMGs give a different picture of the music. Big, brawny sound with lots of punch and power that gives little away to even rock speakers, but imaging is not as precise as the 1.6s, there's a bit of smearing, probably due to the wide spacing of the tweeters on each side, I'd guess. There's so much latatude about placement that I really can't say for sure that the setup is at fault or simply placement or mismatched amps, etc.
The punch and power clearly exceed the 1.6s, as you would expect given the double amps and double power.
Overall, I'd guess that I would have to give the nod to the MMGs. There's probably a bit of precision lost in instrument placement but you can do so many other things that can't be done with two speakers.
If you do play with doubling, try this, you'll get a real kick out of it. Set two of the MMGs about 6ft from the wall, 12ft apart (inner edge to inner edge) and angled sharply inward about 35-40 degrees. Reverse the pair so that the tweeters are on the inside. Place the other two 6ft apart and 3ft from the wall facing forward (no angle), tweeters on the outside. Match the volume levels to all four MMGs and play a good CD, someting simple like the Andrea Bocelli, Songo album.
Start listening at the normal distance and level then slowly walk forward toward the space between the inner pair of MMGs.
At one point, the rediation from all of the speakers blend and everything become 3D. Placement of the instruments firms, depth increases and you are immersed in the soundfield. Play with reducing the level of the inner pair a bit if you can't get it to blend, at some point it will.
The sound may be a bit thin if you don't have a sub because the outer pair of MMGs are really too far from the wall for bass reinforcement.
Some purists will say that what you are hearing is fake, well, maybe their right, but it's fun and exciting to see a sound picture of the orchastra that no two speaker setup can produce. The effect is very similar to the 3d imaging produced by the very best near field setup but with the depth and power of a large installation.
I'm sure that there are some golden ears out there would like to hang me for sound polution, purists that they are.
But what the hell, audio is like any other hobby, something to have fun with. And if I can't have any fun I'd get bored and soon drop it. Then there would be one less buyer of audio gear.