My Pixel XL has been smooth after the initial settling in time, and a few reboots. Battery life may not be as good, but it's been a while since I factory reset my phone. And also, I tend to use it more looking for the new features. I really like what they've done.
One thing that is different since the update, is that my phone will connect to both my Plantronics Bluetooth headset, and my car at the same time. It has always been either or, but today they both connected.
Kinda nice, but I can't figure out how to choose one over the other when the phone rings.