They're a completely different ball of wax in terms of interaction with local acoustics. The dipole aspect of the maggies have greater placement restrictions than direct radiators, considerably further from the back wall for example. Also, they tend to be a bit beamy, resulting in a very constrained sweet spot.
Maggie's can do a few things very well, with fantastic resolution and imaging, albeit limited to the smaller sweet spot. On the downside, the extra dimensionality that dipoles provide is a boon to some recordings but a bit unnatural on others, and since it's inherent to the speakers, it can't be turned off. It's like a sounstage/image enhancing process applied to everything you listen to, whether it benefits or not. It's a bit of a parlor trick rather than accurate reproduction in that sense, which I personally found to be a mixed bag.