I tried a 90D in shop on Saturday.
Not a contender I am afraid. The af through the view finder (a simple near-far test) used with a last gen. 70-400 F4L was slower than I am used to. The tracking af is likely better at a fixed distance, using predictive phase-detect, but I was surprised at how laggy it felt after my Oly gear. The live view focus was good, but certainly no better than anything I have now and not it’s natural state.
To check my feelings on the matter I tried a 5D4, which was noticeably better in view finder af and an XT4 with 100-400 which is still in the mix, but the 90D is out. Shame, as it ticked all of the boxes.
It is also good sometimes to remind yourself where you have come from and how you got there. EM5 mk1, 17mm F1.8