You're joking right? iCloud as a cloud drive destroys every "cloud" drive I have ever used. I am ALMOST back to removing OneDrive, and putting things back on iCloud. I took all my Office Docs off and put them on OneDrive (the updating popups have stopped, so OneDrive as a secondary is OK). I mean I pretty much stopped using Linux as a triple boot or 2ndary boot because GoogleDrive was so pathetic.
iCloud Drive (#1)
Dropbox (2) (this is only used for transfers to people, because of their new Device limit, stupid)
OneDrive (3)
Google Drive (4)
And Contacts... hmm, yeah insanely great, been using that for over 15 years NO PROBLEMS!
NOTE (added): Oh and yeah all iCloud Tabs are working now, except in High Sierra.
But I have over 10 years of Bookmarks, and History, in my Safari (checkbox) in iCloud so...