I owned a pair of MG12QRs, bought them new at Shirley's Hi Fi in Woodland Hills CA and had them shipped to San Juan, PR where I lived at the time. What a great pair of speakers. I will summarize it by putting it this way - upon seeing them set up in the living room, my wife became a tad enraged and rattled "...those are the biggest speakers I have ever seen, they are ugly tall boards, you should have asked me before buying these, you inconsiderate bastard.... bla bla bla <then she shut up as The Eagles started playing and she could not believe how well the guitars sounded>. We spent the ext 45 minutes listening and she never brought the aesthetics up again.
My point about power is: I drove them at first from a Sherwood Newcastle receiver and they sounded ok. Eventually I switched to a Lexicon DC-2 with a PS-Audio 120 wpc amp and they sounded better. Then I borrowed an Anthem MCA5 200 wpc amp and the speakers unveiled a new level of clarity. They are like that - the more watts you give them the better they sound at reasonable volumes. My experimenting never led to damaged amps - but maybe I was just lucky.
Note this:
They suck as far as any sign of deep bass, and you need a *very* fast sub to keep up with them and make a good match in a home theater setting. I have heard Epos and Snell (musical) subs are good fits - I would not know, I went through three Paradigm subs before giving up and accepting them as they were.
The center channel model that matches them was a poor experience for me. By far the worse, expensive center channel I have ever purchased (close to $1k). IMO, get a decent dynamic driver center instead, or better yet use the Maggies for a dedicated 2 channel proper stereo.
I have concluded that the best sound (for me any way) comes from two channel. I keep a nice home theater for movies, but it is far easier to set up a two-channel listening room for music, and the Maggies are great in this role. It may have to do with there being no clear standard approach for properly recording music encoded into more than two channels (witness the failure of quad in the seventies).
At any rate, net of the spousal acceptance factor and the need to spray cat-repellent to the bottom of the grills of you happen to have cats, the Maggies rock. The SMGs are like crack cocaine, they give you a little but not enough. Next thing you know you own MG12s. Now you have me thinking about a pai of MG 1.6s... can't really say I enjoyed life without having owned a pair of those. Hmmm
Pepe