Alright, so what did we learn here? Well, for one, the Galaxy S9+ is not that big of an improvement over the Note 8/S8, but it does produce more natural-looking results, since Samsung has obviously toned down some aspects of its post-processing algorithms. The Pixel 2 XL, while not the sharpest of the bunch, is very good at stacking exposures and producing well-balanced images, even when dealing with high-contrast scenes. Neon signs against a darker background will usually come out blown out when shooting on "Auto" (or the background will be pitch-black if you expose for the sign), but the Pixel 2 XL manages to pull through and deliver commendable results, thanks to Google's awesome exposure stacking trickery. The iPhone X is not as good as the rest when it comes to shooting at night. The images often times come out soft and too noisy for my liking.
If you'd like to see all the photos used in this comparison in their original resolution, with EXIF info available for each one, they can all be found on Google Photos.