It sounds like you're trying to choose based simply on what they look like? If this is the case, then that's entirely subjective and only you can make that decision...
.. but it seems to me there are other, more important, factors to take into account. For example:
- What are you looking to do with it?
- What was your last phone?
- Which app store were your current premium apps purchased from?
- Are you happy to buy your premium apps from another store if you switch?
- Are the apps you want to use on the other app store if you switch?
For my own part, I'm pretty happy with Android, and have never gotten on with iOS (although I'm open to being converted, if someone can tell me what I'm missing out on) - the only thing I dislike is all the crapware that vendors like Samsung put on their handsets - this is why my last 4 phones were either Nexus or Moto.
What I don't know is what the difference between a Nexus and a Pixel is. I've seen a lot of comments on Reddit along the lines of "RIP Nexus" - but surely Nexus lives on, it's just called Pixel now? Or have I missed something?
In any case, I'll be in the market for a new phone in the new year.