One reason is the phone’s superior screen. The AMOLED display makes photos look better; even ones taken on an iPhone. Blacks are deeper, colors are more vibrant and the higher pixel density makes everything sharper.
The camera also performs better in low-light situations, compared with the excellent cameras in the Samsung Galaxy S7 and iPhone 7. In testing, its photos had more dynamic range and color saturation. The only noticeable tradeoff is that some Pixel night shots have more noise (digital graininess)… More at WSJ.
It looks good, really really good.