I would absolutely prefer a smaller, mirrorless camera to a DSLR - provided that dynamic range, colour depth, image quality, exchangeable lenses, the quality of those lenses, build quality etc. are identical to what a D600 or D800 offers. Some of that has already happened, but until that all happens, I'll have to stick with the D600 and D800 I currently use.
I have a friend who has an OMD and shoots beautiful images with it. I'd love to use one too, it even has a viewfinder. But the photosites are I think 3.9µ, diffraction kicks in i don't know how early, dynamic range and colour depth are good but far less than those of the D800.
I think if I were aiming at an APS-C camera, I might look at the OMD as well, or at the Fujis. I would probably not buy a D3200, because the smaller size for me outweighs the advantages in image quality the D3200 may have over the OMD. But if you want the best in sensor quality, I think right now something like the D800 and D600 or the D4 are the way to go.