Google's Pixel 2 XL was well-received and looks like the best Google phone ever. Unfortunately there have been reports of display problems with the OLED screens.
UPDATE 10/11/2017: Users are now reporting a weird flashing that happens when the screen is either unlocked or locked, and also when the Always-On Display feature is activated. Videos have popped up showing the display bug which creates either a bright white flash or a green one.
Google hasn't stated whether it's a hardware or software issue but it has been allowing RMAs for affected devices. If you're a Pixel 2 XL owner and haven't seen the issue, you should be fine. But if it does pop up, an exchange might be your best bet instead of waiting on a software update. The good news is, by the time you get your new unit, other screen problems might also be sorted.
UPDATE 27/10/2017: Google has sent a response to the Pixel 2 complaints. It is extending the warranty to two years worldwide, so that people whose phones are affected by burn-in don't need to worry about getting replacements.
As to complaints that the screen isn't saturated enough, Google insists that a more natural look as compared to the oversaturation seen on competing phones was part of its plan. But a software fix will be issued, allowing people to amp up the saturation if they want to.
The burn-in -issue - or, as Google calls it "differential aging" - is "in line with other premium smartphones" and according to Google, won't affect normal performance on a daily basis. In other words, no, your phone isn't broken but if you still think it is, you can probably get an exchange thanks to the warranty. Or wait to see if the software fix will address it.
Android Central's Alex Dobie tweeted a photo showing a Pixel 2 XL with obvious burn-in, an issue whereby an image lingers far too long on a display. It's a quirk that appears not just on OLED but has surfaced on LCD as well as plasma displays, and is one of those random occurences, much like the odd dead pixel. However, there have been enough reports of it showing up on the newly launched Pixel 2 XL that it could be a concern.
Google's statement, released to media including The Verge, said the following:
The Pixel 2 XL screen has been designed with an advanced POLED technology, including QHD+ resolution, wide color gamut, and high contrast ratio for natural and beautiful colors and renderings. We put all of our products through extensive quality testing before launch and in the manufacturing of every unit. We are actively investigating this report.
It's good to know that Google is investigating the matter. Still, it's a bit worrisome that issues are already showing up so soon. Burn-in is something that typically only surfaces after months, and sometimes years.
The Verge also put up a photo of its own review unit exhibiting burn-in, though slightly less severe than Android Central's. You may want to hold off getting a Pixel 2 XL or even a Pixel 2 until Google sorts out the issue.