Apparently, Pixel has significant connectivity issues: http://www.anandtech.com/show/10753/the-google-pixel-xl-review/7
"Normally we would also run this test on LTE, in order to compare battery life between devices when browsing on a cellular connection instead of WiFi. Unfortunately, the Pixel XL presents a problem here. Both Matt and I have noticed that cellular reception on the Pixel XL is not very good. In particular, Matt was unable to achieve our target signal strength of -90dBm or better in the same area where he tests all other LTE devices. The best signal he was able to achieve was -100dBm (outdoors). Because we're dealing with a logarithmic scale, the difference in transmission power is not 10% like you might imagine based on the numbers, it's ten times the power. Unfortunately, we aren't equipped to do laboratory tests on the Pixel XL to directly compare RF performance to other devices, but it does seem that the signal strength is generally not as good as other smartphones."