I've had my iPhone X since release day, and since release day, it's been a series of apps crashing (and sometimes not loading at all), Face ID being hopelessly slow, the display waking up and voicemail notifications strobing on the screen, music showing up with 3 blank tracks between every song on my car... And all Apple has done is say "Didja reset your phone?"
I had an S8+ that I returned, because I hated TouchWiz, but preordered an S9+. I'm already dealing with bugs and a subpar experience, so I might as well get what I can on the resale market for my iPhone X while it's still valuable.
I'm reasonably sure Samsung's migration tool works with iCloud as well as GMail, Outlook.com / O365, and others. Though, that's assuming you want to use the included apps for that.
I've used GMail and Outlook.com for mail / calendar / contacts for a few years, and they magically appear on both platforms when you log in.