EOS M3 or Olympus E-M10 Mark I?

OK - so you sold the E-M10 (Mk 1 version). I can tell you that the Mk II version is superb - a fantastic camera model whose IQ capabilities punch far, far above its weight. Plus it has a nice retro design and yes, it would be a superb replacement for your old E-M10 Mk I - providing you have a desire to stay within M43. That E-M10 Mk II is one of my cherished "keepers".  And add to this the absolutely superb Panasonic 12-60 F3.5-5.6 OIS lens (which is weather proofed) and you have an absolutely outstanding combination with a great 24-120 MM focal reach equivalent.  And that Panny lens can be had for as little as $250 on eBay (new) - typically separated from the kit.  I've written plenty of times about how this kit lenses (which is weather sealed also by the way) is one of the finest kit lenses on the market - from any brand.  As an aside, that kit lens can be found on eBay - here:

https://www.ebay.com/sch/Cameras-Photo/625/i.html?_from=R40&_nkw=Panasonic%2012-60mm%20f/3.5-5.6%20Lens&_dcat=625&rt=nc&LH_ItemCondition=3&_trksid=p2045573.m1684

So now let's discuss the EOS M line of cameras. First of all, there are quite a few folks on this forum that shoot with a variety of systems - whether that be Sony, Fuji X, Micro 4/3 or whatever. I still maintain the M, M2, and M3, along with the newer models of the M50 and M100. And since you mentioned "Canon colors," you'll find the older M and M2 exhibit those traditional Canon colors. The M3 modifies it slightly, slightly changing the hue of this traditional color tonality and even at times with the M10. And yes, at times the M3 has a slight greenish tint, which can be offset in post processing if you shoot in RAW. But IMO, I find the M3 to still be a delightful camera to use. I personally keep the 11-22 (now) on it and they make a wonderful combination.

Do keep in mind that if you look on eBay, there are quite a few outstanding vendors there where you can find excellent EOS M series cameras (new) for some fantastic prices, and that's where I've purchased just about all of mine - to include EOS EF-M lenses. You don't have to go broke looking for the right EOS M body, that's for sure. But if the EOS M3 is all you can afford, I'd also look at the EOS M10 and EOS M100. I used to have the EOS M10 (until I got the M100) and found it to be delightful - absolutely so! No, the M10 and M100 don't have options for an external flash and I found the AF to be just fine for most of what I used them for (general photography scenarios). But I don't think you'd be using an M10 or M100 for sports scenarios anyway. Remember, anything produced after the M10 is 24 MP's (as opposed to the older, yet still very capable 18 MP's that you find in the M, M2, M3, and M10).

Here are a series of samples - some scenes very similar to each other - taken by the M10, M100, and M3, and you may be able to detect the slight differences in color tonality. I will list the camera and lenses used with each image. Do note that the EXIF data is not there because I use Irfanview, which is an excellent free batch conversion program to create JPG's for web display, When you convert from TIF to JPG in Irfanview, the Exif data is stripped unfortunately (it's an issue with the software, but one that the developer will not tackle). All images were shot in RAW mode and converted with either Lightroom or ACR within Photoshop.

M10 sample images - all taken with the kit 15-45 lens (not the greatest copy of the lens, but a half-assed decent verson of it):

M10 with the 15-45

EOS M10 with the 15-45

ISO 3200 - M10 with 15-45 kit lens.

M3 Images - various lenses used to include the Tamron 18-200 F3.5-6.3 Di III VC for EOS M mount.

M3 with the Tamron 18-200 F3.5-6.3 Di III VC lens for EOS M mount.

M3 with the Tamron 18-200

M3 with the Canon Ef-M 18-55.

M100 images with a fairly good copy of the 15-45 lens attached:

M100 with 15-45 kit lens

M100 with 15-45 kit lens

M100 with 15-45 kit lens.