I had the first Note, and then a number of different Samsung phones, until the S8+, and now the Note 8.  In the meantime, I have tried a few alternatives, and I didn't like ANY of them.  AT ALL.  Here's what I prefer about Samsung, the most:
1.  Wireless charging.  I won't have a phone without it.
2.  Flip covers.  Open the cover, and the phone turns on.  Close the cover, and the phone turns off.  Simple.  Perfect.
3.  Samsung "bloatware."  Frankly, I prefer how Samsung does things.  Boy, did I miss things like Samsung's music player and video player when I've tried something else.  For instance, the music player will play by FOLDERS.  I have managed to avoid "playlists" my entire technological life -- who needs them, when you can just use folders, instead?  There are plenty of music player apps that simply won't play by folders.  And so on.  I like Samsung's interface, its launcher, and so on.  Works for me -- very well.
Now, let's talk about the screen.  For those who can't comprehend why Samsung uses them, the curved screen allows for a phone with a "wider" screen that isn't as physically wide as a flat-screen phone.  So, that's the reason for it.  That said, I'm not really a big fan of the curved screen -- I would prefer a wider phone with a flat screen, but it's obvious if you want a Samsung phone with a large screen, that screen will be curved.  But in the end, the narrower phone fits in places a wider one wouldn't, and the Note 8's curved edge is "less curved" than previous edges.  I also prefer the Note 8's more rectangular body than the S8's more curved one.
So, what do I like about the Note 8 over the S8+?  Some it is what I just described above, about the screen and the more squared nature of Note 8.  While the screen isn't much bigger, the squared corners actually help to make the difference a bit bigger.  Of course, the extra memory should help the Note 8 perform better.  I really didn't buy the Note 8 because of the S Pen, but I'll play with it and see if I can get some use out of it.
But for me, the biggest difference is the dual cameras. I really don't care about cheap effects and such -- I just value having some effective "optical zoom" by using the second camera with its 2x lens.  I have been happy with Samsung's top-of-the-line phone cameras, to the extent they can take pictures without zooming, so having a 2x optical option will allow me to just depend on my phone and leave my cameras at home, to a far greater extent.
In the end, that may not be enough to justify spending the extra money for the Note 8, but unless Samsung launches a non-curved large-screen phone some day, I expect I'll be able to live with the Note 8 long into the future, keeping it far longer than any other phone I've ever owned.  That's the plan, at least.  But in the end, I was happy with my S8+, and I'm quite a bit happier with the Note 8.