The 8+ is exactly why Apple's iCloud ecosystem is so important for lock in. I had the "misfortune" to see and hold one of these things and it makes my 7+ feel like an antique, not dissimilar from the way my first iPhone made my old Blackberry feel.
I know you can port everything over, and operate within an iOS environment (my family all have iPhones, we share calendars, iTunes sharing/accounts, etc.) but doing so is a PITA despite what many of the "easy" switching guides indicate.
Said another way - if I could use iCloud on this I'd buy an 8+ so fast it'd make your head spin.
Apple better deliver with the iPhone X or whatever it'll be called. They have real competition on the hardware side now.