The Pixel and Pixel XL maintain the 0.5 difference in screen size, but drop to 5 and 5.5 respectively. Aside from screen size and the battery, the two metal body phones have virtually the same hardware. Google Pixel keynote
Both now use AMOLED screens - this is a requirement for Daydream VR, they can change pixels faster with minimal ghosting. The screen has to have at least 1080p resolution, further the phone needs 4GB ( or more) of RAM and run Android Nougat. This is essentially the 5 Google Pixel.
Google Pixel at a glance:
Body: Metal unibody
Screen: 5 1080p AMOLED screen ( 441ppi) ; Gorilla Glass 4
OS: Android 7.1 Nougat; Android Assistant
Chipset: Snapdragon 821
Memory: 4GB of RAM; 32GB or 128GB storage
Camera: 12MP ( f/2.0, 1.55µm) ; EIS, 8MP selfie camera
Video: 2160p
Connectivity: LTE ( Cat. 9-12) ; Wi-Fi calling; USB Type-C
Battery: 2, 770mAh ( 32h talk time, 552h standby) ; Fast charging ( 7h talk time in 15min)
Misc: Fingerprint reader
The larger Pixel XL goes up to QHD resolution and a higher pixel density. It has the same amount of RAM and storage options, though - 32GB or 128GB. Before you ask, theres no microSD slot, but Google Photos can free up storage by moving photos and videos to the cloud.
The LG V20 may have been the first phone with Android 7.0 Nougat out of the box, but the Pixels one up it - literally, they come with 7.1 Nougat. Google Assistant is Google Nows more talkative, more pro-active sibling. It promises to learn the more you use it and become more helpful in time.
Google Pixel XL at a glance:
Body: Metal unibody
Screen: 5.5 QHD AMOLED screen ( 534ppi) ; Gorilla Glass 4
OS: Android 7.1 Nougat; Android Assistant
Chipset: Snapdragon 821
Memory: 4GB of RAM; 32GB or 128GB storage
Camera: 12MP ( f/2.0, 1.55µm) ; EIS, 8MP selfie camera
Video: 2160p
Connectivity: LTE ( Cat. 9-12) ; Wi-Fi calling; USB Type-C
Battery: 3, 450mAh ( 26h talk time, 456h standby) ; Fast charging ( 7h talk time in 15min)
Misc: Fingerprint reader
The cameras use 12MP sensors with 1.55µm pixels behind an f/2.0 aperture - it sounds just like the Nexus 5X/6P camera, which was excellent. Its not a verbatim copy, new Electronic Image Stabilization is present.
The talk around town is that Android and Chrome OS will merge in the near future, but product branding is already merging - Pixel was used for the premium Chromebooks and later for a first-class Android tablet. However, this is the first time it embodies a phone.
HTC is the company manufacturing the Pixel and Pixel XL - a 5 and a 5.5 version of mostly the same hardware. The Taiwanese company is going back to its roots of an ODM - a Pixel is a Phone by Google, theres no endorsement of HTCs involvement. Google is about hardware now and its only braning well see from now on on these devices.
This stands in stark contrast to the Nexus line - they were branded Nexus and with their manufacturers logo. But the Pixel phones are not the new Nexus phones - Google is rebooting the entire lineup. The search engine company is no longer a software company - its now in the consumer electronics business as well.