I'm considering the S8 or the G6 but being unfamiliar with Samsung's or LG's software I'm not sure if I'll like it. My previous phone was the moto x so I've gotten used to the stock experience for the past several years with that and the 6p. I welcome all comments from anybody with experience going to/from either of these or similar devices.
I'll share my experience.
I have started my Android journey with Samsung S3. Coming from blackberry, I loved it. I then moved in to big phones starting with Note 3 and then Note 4. When Nexus 6 came out, a 6 inch screen got me excited and made the jump away from Samsung into Nexus world. And oh boy did I LOVE IT. I swore I would never go back to carrier bloat and Samsung lag. I lived and breathed Nexus for few years and had 6, 5x, 6P and most recently Pixel XL.
As much as I enjoyed pure Android, deep inside, I still missed Samsung Note series. When Note 7 came out, I was seriously thinking about going back until it started catching
The last 2 weeks, I made the switch from VZ to AT&T, and with that, I got a great deal on a S8 Plus, and oh boy was I in for a pleasant surprise. Samsung has come a long way since I've left them back when note 4 came out. UI is so smooth I didn't believe I'm holding a galaxy S phone. I have had Nova launcher on all my phones, and nope, I have not even needed to install it in my S8 Plus.
Camera, amazing.
Build quality, amazing.
Screen, holy cats.
Water resistant, why not.
Wireless charging, use it all the time.
Smooth, never thought I will say that about a Samsung phone.
Infinity wallpapers are so refreshing.
Expandable storage, I have 128gb to hold all my pictures, and music, leaving internal 64gb for apps.
Only thing I changed was installing Gboard as I am still not a fan of Samsung keyboard.
In short, Samsung won me back big time. I now can not wait to see what the Note 8 will bring. Definitely getting that one when it comes out.
Hope this helps. If you decide to make the move, get the S8 Plus, especially that you are coming from Nexus 6P. I honestly don't think you will regret it unless you care about updates on day one. Not me, not anymore. Android O and P will make their ways to S8 Plus, just not on day one and I'm so very much ok with that.
Good luck!