That is promising. I am using the two year old Nexus 6 and the readability outside in sunlight (or even near a window) is poor. According to this chart, http://www.phonearena.com/phones/Google-Nexus-5_id8148/benchmarks , my N6 is 270 nits and the 6P is 356. Greatly improved brightness and camera were the two things I really wanted from the Pixel (XL) and it sounds like it will deliver on both.Just to get back on this. The panel is actually the exact panel used in the Galaxy S7 Edge. Confirmed by Anandtech.
The S6E3HA3 panel is the one used in the Galaxy S7 Edge. Note 7 uses the S6E3HA5.