I have shot Canon SLR's and DSLR's since 1998 and Canon point and shoot longer than that. I have no qualms about Canon quality, especially with L level glass. But last year at Yellowstone, the weight of a 7D with battery grip and the 70-200 f/2.8 II just became too much. And a full kit is now almost impossible to get into a legal sized carry on for air travel.
So. last January, I sold my 70-200 (on this forum) and bought the Olympus OMD-E-M1 body and 12-40mm f/2.8 Pro lens. Sort of a trial run if you will. I figured I could back out and return to Canon if the Oly gear was not up to snuff.
Well, it's a year later and I now have a rather complete set of Oly lenses, with the new 40-150mm f/2.8 Pro just arriving. Honestly, as Olympus fills out their Pro line of glass, I can't think of any reason to stay with the much larger and heavier Canon gear. In my opinion, the sensor and image quality is far above the 7D (don't know about the 7D Mk II) and the body is built like a Swiss watch, with more pro features than the 7D for sure. While waiting for Oly's 300mm f/4 Pro lens (remember, field of view is twice 35mm) I still am using my Canon 400mm f/5.6 manually with an adapter. My expectation is the new 40-150mm f/2.8 will track moving objects well, even close to the 7D. I'll report back as I get a chance to use it that way.
My wife's Christmas present is an OMD-E-M1, 12-40mm f/2.8 and the 40-150mm f/2.8. So we are now well on our way to Oly Land
I much agree with Michael Reichman's comments on Luminous Landscape that 16 MP on a 4/3 sensor is enough for anything short of huge prints. So far I am very pleased with Olympus's offerings and really like the smaller size and lighter weight. Now, with the forum being open to other brands, I look forward to posting shots here and discussing the pro's and con's of the switch.
Look for a lot of Canon gear on the for sale forum in the coming weeks.