The last Olympus camera that I owned was an E-P5. This was actually the last, expensive non-Canon body that I owned.
At the time, nearly all the photography that was important to me was either macro (miniature subjects about 2" tall), or garment stills, where it was important for something like a sweater to fill at least about 12MP (3500x3500 or higher resized), have a both a pleasing image when zoomed out, and clearly see the thread and yarn of the fabric when zoomed in, with no softness anywhere on the garment. Things that were really important were, for example, the ability to perfectly represent embroidered logos, since the application allowed you to move a magnifying glass over any part of the garment and see it at pixel-level, based on a 12MP-ish image (chosen because of file size).
Though I generally enjoyed the camera, unfortunately, the Olympus E-P5 was not really great at either task, though it was dubiously acceptable. Eventually, I sold it. Is the current generation of Olympus going to do the task? Maybe, but I would be surprised. I'm not really willing to take the time and energy and cost to try, now, and besides, I'm happy with Canon.
Specifics: The sharpness that I can get out of a 50mm 1.8, 100 L 2.8, and 24-70 L 4 on an 80D is simply amazing. Even at full resolution, going to 100% gives me perfect crispness on any corner of the image, which future-proofs my unresized photos -- it's very possible, as 4k monitors and faster internet become more common, the client may one day ask for higher resolution than 3,500 x 3,500. Since most garments fit a rectangular bounding box rather than square, it's quiet easy to get 6000x6000 out of a 24MP image, and since I did all my post based on the maximum image size, I could charge a whole bunch of money for doing, well, nothing.
Now, who knows, maybe I was doing something wrong with Olympus, but when photographing miniatures (models that are a few inches tall at the most) for the purpose of reprint onto full page letter/A4 sized magazines, the Olympus did not really produce acceptable results at all. I can't recall what lens I had anymore, but I'm sure I spent close to $3,000 on the system, and added to it for a while. I made my images work with Photoshop, but it was a real chore. With 80D, the most I have to do is get rid of tiny specs of dust that manage to get onto the subject between being cleaned off and being photographed.
It's also worth noting that the RAW support in various tools is just WAY better for Canon cameras and lenses than Olympus. Again, maybe that's changed, but I don't really care anymore, because I'm happy where I am.
The main reason I got a 6DII (other than, I wanted one) is because it allows me to take larger subjects on where space is constrained. There are some that are really huge, like work coveralls, or sometimes, I have a request to photograph items on a mannequin or live model, but in a space that isn't very large.
