I pre-ordered the Spigen Nexus 6P Thin Fit case and a Spigen crystal screen protector back when I pre-ordered my phone. I had the Xtreme Guard screen protector and Adopted case from Google with my phone. The case was ok, but I'm not a fan of how it covers the side buttons. The screen protector was rendered worthless by the case, as the case would peel up the edges of the screen protector during installation. I figured the case was more important than the screen protector, so I went without the screen protector while I waited for the Spigen stuff to arrive.
I didn't like the Xtreme Guard screen protector even before ruining it with the Adopted case, because it is one of those softer cases that makes the screen feel, I don't know, squishy. You can dig a fingernail into it and it's tacky. It's not smooth feeling at all like a glass screen. It might protect the screen, but you give up a lot of screen feel in the process.
The Spigen crystal protector is what a screen protector should be. You can see the edges around the speaker ports and sensors, sure. But, to the touch, the screen protector is invisible. It feels like the glass screen.
The Spigen case is perfect for my needs. I don't need anything super protective. I want m phone to be protected from minor scuffs and drops, and I want to be able to put it down on various surfaces without worrying about beating it up. So, I like minimalist cases. Spigen hits the mark. If you liked the thin snap case for the original Nexus 5 from Google, this is its twin. All ports are nice and open, and the back has just a thin shell on it to let you lay it down on any surface, worry free. It should also protect against minor drops. If you aren't too hard on your phones and like your phone to feel like it should and less like a big rubber brick, this case is for you.