I've had a pretty good experience with return/replacement process both for my Nexus devices (my 4 was rock solid, my 5 needed replacing twice, my first Pixel2 lasted a week but had a battery fault and was also painless to replace) but at the time I was in the US. Now I'm back further from their logistics center I'm a bit more worried how things will be handled in the future... that, and the awful leak photos of the be-notched Pixel3 makes me suspect I'll need to look elsewhere.
As the price tag has gone up every generation the incentive to actually upgrade has gone down, especially with things like headphone jacks and SD cards disappearing (the first annoys me several times a week because I've already lost two USB-C to 3.5mm adapters!)
For me, the big selling points of the Pixel have been the camera, the minimalist skin (though I do still prefer and tend to revert back to, Evie) and the regular as clockwork updates. If Nokia live up to their promise to deliver the same then I may switch back (less about the nostalgia the name evokes, but based on their ability to deliver on their promise to rekindle customer loyalty by building and supporting good hardware).
I keep thinking a switch to the iPhone would solve my complaints with the Android ecosystem, but ... https://medium.com/@offbeatmammal/apple-are-a-design-company-so-why-is-ios-so-annoying-d40530dce8d9