After testing my friends unit, I think there's a couple of improvement over S8. It's slightly faster, probably due to more ram. 2nd camera works like charm.
What I'm really surprised is the S Pen. This is how the S Pen should be years ago. The fine tip is great, feel like writing with pen. But what really surprised me is the accuracy. The writing is really matching the tip now as opposed to previous version where you have to hold it in a certain way. This is why I dislike S Pen after a couple iteration without this refinement.
Samsung Note 8 Discussion Thread V2 (Samsung)