Most of the concerns about AF is regarding video. Why this ever becamse a priority spec on FF pro spec bodies I'll never know, plenty of more dedicated vido-centric cameras out there.
From what i seen, for the stills photographer, it looks the nuts.
One other thing that bugs me is this dual version thing they are all doing now. Why do they need 2 different res versions? why not just one somewhere in between? Kind of p***es me off that after all the years of the 'experts' telling us we don't need a high MP count, they are now hailing these companies for doing a higher res 'pro' version - i.e, just more mp ... There might be a couple more features chucked in to justify the price hike but all I see is higher MP count on say the Z7 or A7RIII, now the S1R - complete rip of what Nikon and Sony already established.
Besides all that, the Pany S bodies do look pretty beastly. When looking up actual reviews as they come along bear the whole vlogger/video side of things in mind though, a lot of what reviewers moan about these days is lack of features for that market, should be completely separate. Most photographers I know never touch the video functions on their cameras and certainly don't need or desire flippy screens. It's the one feature I dislike about my own current camera.