Galaxy S9 vs Pixel 2 XL: Display
The next category is the display for these two phones, as that's an extremely important area for most buyers.
Samsung's Galaxy S9 comes with a 5.8 or 6.2-inch Quad-HD display, the same sizes as last year. Thanks to small bezels though, these phones aren't nearly as big as they sound.
The Pixel 2 XL has a perfect middle ground here, coming in at 6-inches. If Samsung's phone is too big or too small, the Pixel isn't. That said, Samsung's Galaxy S9+ with a 6.2-inch screen is actually physically smaller than the Pixel 2 XL. Those bezels and dual-front facing speakers make the Pixel the bigger of the two. So keep that in mind.
Size aside, both of these phones have amazing AMOLED displays that look great. If the size isn't a huge concern and you simply want the best, Samsung wins again here. There's no denying Samsung has the best screens in the business. The Pixel 2 XL has a display from LG, which is decent, but it's no Samsung.
You'll love either one, but Samsung gets the go-ahead from me.