I've only owned the 2XL, and it's my current device, but the vote for me is easy because of stock Android. The Note 8 is no doubt phenomenal hardware and would scream with stock Android, but it's got Samsung's software alterations, which minor or major, will inevtiably cause issues at some point or another. I owned the S8+ very briefly and while it was fantastic hardware, I could not get on with 'Samsung Experience'.
You also can't put a price on timely software updates - something only the Pixel can offer. Similar to iOS, when Google releases the update, you get it. There is no waiting for Samsung to get it, modify it, then wait on a carrier to push the update. Also, no bloatware.
I was a very long time user of iOS looking to move to Android, and I dabbled with a few devices over the years but nothing can match what the Pixel 2XL gives me and I have zero regrets about breaking free from the chains of the Apple ecosystem.
Be aware of the QC issues that have come up with the 2XL though, and understand that it's still very much a lottery. I seemingly got a very good device, but not everyone has.