I'm coming from a Moto X Pure (2015 model).  The touchscreen stopped working (out of warranty) in a really bad way, so I bought the S8+.   I would not buy another Moto because of the issues with the  touchscreen.
Screen issues set aside, the Moto was a decent phone, I liked the interface better and was about half the price of the S8+, but updates were few and far between and was still waiting for the promised Nougat update that never arrived.  Had the Moto not died on me, I would have waited for the Pixel 2, but went with the S8+ because it had the fastest processor and I'm happy with my choice.  
I like my S8+with its nicer display, better battery life, slightly larger display, like the 18:9 aspect ratio, the list goes on....
The S8+ seems more fragile than the Moto.  It a nice looking phone that unfortunately have to keep covered up with a substantial case to protect it.  
I hate Bixby and wish the Bixby button was not there because I always seen to press it accidentally while pulling the phone out of my pocket.
I also have a few pet peeves that hopefully can be fixed with a software updates.  E.g. can't tun off Google Navigation Voice over Bluetooth, screen turning on in my pocket when making/receiving calls over Bluetooth, screen randomly turning on in my pocket for other reasons.