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.