OMD EM-5 compared to Nikon D800

I mainly shoot a lot of landscapes scenes, and I am wondering just how the EM-5 compares to the D800.  I have read that the D800 was a great camera for shooting landscapes, but I have gotten some nice landscapes with the EM-5 as well.  I guess that I am asking if anyone have shot with both cameras and have any suggestions on the images that they have received from both.  I print my images up to a maximum of 11x14, and I am just wondering if that is a size that would even be noticeable in either image.  I have thought about buying the D800 and shoot with both cameras.  Let me set everyone straight, I am not thinking of getting rid of my EM-5, I love shooting with it too much?   Anyone have any ideas on of how they would compare?