Nexus 6P vs Note 5: Software
One thing that millions of buyers will want to think about is software. While Samsung has pretty great software loaded with tons of features, many don't like the bloated approach with so many options that it can get confusing. Samsung's TouchWiz covers stock Android 5.1.1 Lollipop, but should see Android 6.0 soon, hopefully before the end of the year.
The S-Pen stylus and Samsung's array of software apps allows users to write on the screen, take down notes, write while the screen is off, edit stuff, run two apps at the same time and more. It does a lot, but many users also don't use the S-Pen, and just want the huge screen.
If you're one of the latter, the Nexus 6P is perfect. It runs pure vanilla stock Android 6.0 Marshmallow made and delivered by Google, will get the fastest updates and always be first to the latest software, and isn't as bloated with features, options, and carrier apps.
Samsung's TouchWiz this year is one of the best yet, and doesn't get in the way too much, but it's still TouchWiz. Pure Android Marshmallow has tons to offer, will continue to see updates, and be a very simple, clean, and smooth experience for all.
This choice comes down to stock Android and price if you ask me, but everyone has different wants and needs.