These were my two choices too and I went with the LG V30. Full disclosure though my ATT store does not carry the Pixel 2XL but I could have bought one and used it there though.
My LG V30 is brand spanking new so I dont have the experience as most have but I can tell you what I have learned by using it for a short while. At the ATT store and right out of the box I took a few pictures with it in auto mode and the came out looking great but that is in auto and in a pretty lit up room so that is to be expected.
When I came home I set up my wifi and some other stuff as a new phone would do so after a little while the wife and I went for a walk at just after dusk so I brought out the camera and took a couple of shots in the dark and I was impressed and that was in auto mode.
Then I tried Manual mode and thats what I love as I have a DSLR and I love taking photos in manual, The LG V30 is really good, I couldnt believe it and then I tried the video in the dark at a street which had only a few cars driving by and that came out good as well and that was before the Oreo update.
Btw, the update does take awhile at least it did for me. So its very late now so tomorrow I'l take some pictures and upload them, hopefully (LOL) but one thing that I noticed right off the bat was when I came home from ATT and started doing some things to it I saw that the battery was draining very quickly but after the Oreo update it was better but I will test it and report back in with what i find.
I am VERY excited with what I have seen and I hope that after a couple of days this phone works out for me as I really love it so far.
Regards, Jake