I had both. First the MMG's were smoother, less revealing, less dynamics, shorter soundstage. Just less of everything but the MMG might be more musicial. The MG-12's more of everything and not much bigger.(the 1.6 are way bigger). They both are nice speakers but the two things that made me to move on were, the shorter than normal soundstage height and ear (listening) fatigue on the MG-12's. You have to listen at higher than normal(all Maggies)(I like low levels) listening levels for them to come alive.(also harder to set up to sound there best). Could it be efficiency and dynamics? A sub. might help?
I went to a high eff., dynamic speakers, with tube int. amp and different cables.I like them alot. But I do miss the Maggie sound at times.