There are three issues with Maggies. The first is an problem that all bipolar speakers have, which is that they produce a back wave that is out of phase with the front wave, and reflects off whatever is behind the speaker, and interacts with the front wave. So you have to have them out from the wall several feet, and you have to be willing to experiment with location alot to get the best sound out of them.
The second is a problem all line sources share, which is that they have good dispersion in the plane perpendicular to the line, but almost none in the plane parallel -- by which I mean, if your ear is above the top of the speaker by more than an inch or so, there is no high end at all. So don't stand above them.
The third is a particular problem with Maggies. They are made with wires glued to membranes, and those wires come loose, and rattle. It's horrid sounding. They can be reglued, but it's work, and if you don't know what you are doing, you might not do it well. Magnepan does sell repair supplies and offer advice, but if at all possible, play them loud and listen for rattles before making a decision.
Having said all that -- not everyone likes the sound of planar speakers because there is less sense of bass and more sense of room, which can be disconcerting at first. But if you like them, its very hard to go back to the boxy thick resonant bass of normal speakers.