M4/3 is equivalent to APS-C for all practical purposes (my opinion). I could only get "better" photos using full frame gear. Better is exceedingly subjective. My needs are different than others, but suffice to say I can print a poster size print from my Oly with no issues. I'm not going for commercial photo needs, so that is fine with me.
Part of the subjective nature is that Canon processes differently than Oly. That is all software related. All the processor does is speed it up. For JPEG: Oly colors are really good out of the camera, and sharpening is tolerable. Noise reduction is too strong at high ISO. Canon can oversaturate out of the camera, sharpening is good, and noise reduction is also too strong. If you just work with RAW, then neither does anything differently since you get exactly what the sensor saw with no processing.
The processor only affects speed. Better processor, faster shutter speeds, and shorter times to clear the memory (also called the buffer). The flagship speed cameras usually have 2 processors for this reason.
Lens wise, both systems offer great ranges. From a sharpness standpoint, Oly has better consumer level lenses, IMO. In terms of breadth, Canon wins. Mirrorless design or not, their mirrorless cameras work well with their legacy lenses. And no one will ever complain about the quality of an L series lens.
That said, you have Panasonic to pull from as well making the m4/3 system pretty complete. The only thing missing is good 3rd party support. Don't discount the Pana/Leica lenses. Between the two, you cover all the focal lengths from near to far, and most f stops. It's up to the photographer to fill in the blanks. All systems have that tenet.
We get all caught up on sharpness, and color rendition, etc. Any camera can take a great photo, even an Iphone.
Jeremy