Recently I posted some photos taken from my D800 and E-M1 on dpreview, and some of the forum members requested that I do some photos that showed all three cameras - in particular, the D7000 with 85mm f/1.8G lens (135mm at 35mm) compared to the E-M1 with 75mm f/1.8 lens which is 150mm at 35mm. I've also added the D800 with 105mm f/2.8 lens, just for comparison. Here are two sets from this afternoon, when the sun suddenly decided to come out and gives us some nice lighting. Both taken wide open at the lowest available ISO. All photos are full resolution; the D800 ones were compressed at 80% to fit into the Wordpress requirement of 10MB, the D7000 and E-M1 ones were compressed at 90%. No editing was done in Lightroom, and of course Adobe's Camera RAW handles the RAW conversion differently for each camera. Click to pixel peep.
These all look pretty similar, though if you pixel peep you can see some chromatic aberration going on in the D7000 and E-M1 shots.
These next three were taken with a slightly more difficult focus requirement: the front of a bunch of moss sitting on top of a fence post. As you can see, these were all taken at ISO 400.
Conclusion: you can have fun with pretty much any camera.