No way I'm going back to Samsung. I had Samsung Galaxy S3 on Verizon, and it was a mess of battery-eating junk. I had to root that thing to get rid of all of the unwanted Samsung and Verizon apps, and get the battery consumption down to a reasonable level. Knox was the last straw for me, couldn't even use a ROM at that point, although I kept it rooted so that I could keep throwing out apps as I needed to.
The 6P is a great bare-bones Android experience. Really like it, and using it with Project Fi is saving me a bunch of money over Verizon. Even gave Android N beta a try, just for fun. That worked fine with Project Fi, and looks like it's going to be great when it's mature. Even if I was back on Verizon, I'd still use the 6P, so that I had the same bare-bones Android experience there, got timely updates, etc...but I don't see any reason to go back at this point.
Anyways, I really like the Nexus 6P, no way I'm going back to a Samsung phone. Don't have to root it, and the "doze" functionality (or using "wifi only" with Project Fi) keeps the idle battery consumption good. "Aggressive doze" with Greenify also helps, if you're like me...I don't see any reason that my phone should use up my battery when it's idle. Android N has "doze on the go", which is just like Greenify's "aggressive doze"...the phone doesn't have to be horizontal or idle for an hour for doze to kick in. It can be in your pocket, and if it's idle, doze kicks in. On the other hand, if you get text messages or calls in doze mode, they come through. So that appeals to me (and really does work).