It's interesting reading this thread because I did the exact opposite. I went from a Note 8 to the iPhone X.
You will absolutely love the Note 8. It is a phenomenal phone. Incredible screen. Incredible battery life (if you are smart with some of your settings). Incredible camera (although the camera app can be a little cumbersome when coming from the simplistic one of the iPhone). A plethora of bio-metrics to choose from (Iris scanner is 100% the best). A headphone jack, the S-Pen and Samsung Pay.
But as I was using it, I missed my iPhone 7 for two reasons and two reasons only: iMessage and One-handed use. There is simply nothing that comes close to iMessage on Android. Right off the bat make sure you download Textra and use that as your messaging app. It is good with sending no-limit MMS files, if you make a small change in the settings. When it comes to the Note 8, one handed use is virtually impossible without a hand placement shuffle/dance. Keep in mind, I have very gargantuan hands. When you do that dance, you get a moment of fear that you may drop the phone because the glass is slippery. I would highly recommend a grippy case. If you run the Note 8 naked, and try to do the shuffle dance, you will drop it at some point if you aren't careful. When you use the Note 8, you will certainly want to use your left hand for security and right hand for touch.
There are two things I will miss about the Note 8. One is the screen. My god, if you consume a lot of content, that screen real estate and quality especially if you do your own color balancing in the setting, is on its own level. People will tell you the Note 8's screen is over-saturated, but they are clearly ignorant to the fact that you can very thoroughly optimize the phone's color profile to whatever you want (an option that more manufacturers need to give their consumers). The second thing is notifications. There are an absolute mess on iOS. It's significantly better and more organized on Android. I forgot how refreshing it was to have notifications cleanly grouped.
Enjoy your Note 8 man. You are in for pleasant surprise.