If someone offered to trade me a new note 8 for my Oneplus 5, I'd accept.
Then I'd sell the note 8 unopened, buy a new Oneplus 5 and pocket the extra cash! ... Actually, I probably wouldn't... Seems like effort.
To be honest, it depends what you want... If you want the fastest and most powerful phone, go Oneplus. If you like the "value added" Samsung stuff like the ****tier version of Google now with a hardware key, or a better (not best) camera, the actual best display or the bezel thing or stylus, and can put up with the crappy biometrics, go note.
So you feel the OnePlus 5 is going to be more powerful than the Note 8? Why? Specs? Hardware?