These things are certainly subjective!
Water image - I prefer the Pixel for its colours
Woods - iPhone definitely. Although the Pixel picked up a lot more detail in the shadows, it just ends up looking fake and nothing like what you see in person, like a lot of night photo modes on cameras. It looks as if a harsh white flash has been used, and a lot of the shadows have that weird purple-ish tint to them that looks like chroma noise, like when you try to brighten the shadows on a jpeg and the dynamic range just isn't there. Just looks flat and unpleasant. iPhone's results have more shadows and a lot less detail on the ground etc, but a much more natural look to them overall like that's what you'd expect to see with your eyes. It's a great example of how the tendency of many cameras (and photographers) to try and pick up every detail as if it's daylight-exposed is not necessarily a good thing. It's a machine's way of thinking rather than an artist's.
Portrait - not a lot in it really. I think I'll give it to the Pixel as the skin tone looks more natural to me (but I've not seen the guy in person so maybe the iPhone is more accurate I don't know) and it's also picked up more of his facial hair detail. But one's taken at a wider angle than the other so it's hard to make a fair comparison. A lot of people may prefer the "popping" rich colours of the iPhone so it's down to the usual personal preferences between natural and vivid.
Shopping centre - the iPhone's colours are much nicer IMO for the same reason I actually preferred the Pixel in the water image - I prefer the warmer look, it looks less "harsh" if you will, rather softer and more inviting.
So it's something of a balance really. I'd maybe give it to the iPhone overall as I think where it wins out it tends to be more pronounced than when the Pixel wins. On the other hand, if you have the time to edit all your photos the Pixel possibly has more detail to play with and you can always boost the colour temperature, darken the shadows etc. Question is, who has time for that? It's good to have photos that look how I want them straight out of the camera.