Really enjoying it.
The open world style gameplay of Chapter 4 marks a bit of experimentation for Naughty Dog, and despite not overly liking open world games for the lack of a linear direction and often too much travel involved, I feel they done a great job of mixing things up, while keeping the focus.
The end of Chapter 6 also has one of my favourite moments of any Uncharted game. I was grinning from ear to ear like a child.
Graphically I think it's a step up from Uncharted 4. I find myself in photomode a lot, just zooming around looking at things from different angles and tinkering with the settings. The start of chapter 6 with the weather effects and atmosphere is pretty impressive, and some of the jungle scenes in chapter 5 with the fog are just incredible.
It's the design though that puts it head and shoulders above other games. It's just so well crafted. I can't overstate that. Everything in the world has obviously had attention poured into it. From the angles of sunlight as you emerge from a tunnel, to the level desing that constantly makes you stop and take it all in, vertical structure of fightscenes adding choice, to the weapons, combat, audio, and even how to the AI interact with the environment, it's just dripping with details that suck you in.
The pacing is also brilliant, the escape scene near the beginning is one of the best.
I haven't finished it yet, but it's up there with one of my favourite uncharted games so far.