These are wonderful speakers for surround duty. I have used them with both MG 12s and MG 1.6s. They blend well with other Magnepans and provide excellent ambient sound for music and nice for directioanla nd dedicated 5.1 theater. Over $725 I think few rears have such a 3D image that these speakers provide. Unlike other Maggies they don't require loads of power and south very good with modest amplification because they are not full range speakers. I have yet to use them as front speakers but as rears they are amazing.
Listening to a variety of movies the speakers give a open sound that gives a real feeling that you are sitting in the middle of the film or music. They are also the only speaakers besides other Magnepans that can really blend with my Magnepans as well as they do. It doesn't sound like 5.1 when they are working but rather a uniform driver that I am in the middle of. There abilityy to fill a room with sound and provide a good soundstage is amazing for this price range. This is probably due in large part to thei wall mount design that lets them reflect off the wall and give a large soundstage. I would recommend this speaker to anyone even owners of SS1s. My father used to own SS1s and the MGMC1s sound fuller though they still only go down to around 80-100hz. The treble and midrange is also a lot sweeter and so it blends better with the floorstanding Magnepans.
These speakers are an excellent buy in my opinion and worth the purchase. These are probably the best surrounds you can buy unless you have the space for larger Maggies in the rear.