The Thinkpad X1 Carbon is 1600x900. Surprised that is not that well-known, as you're the second person on this thread I've noticed with that misconception. I upgraded from my old X200s to the X1 Carbon and it's great.
1600x900 is lower than 1920x1200 and even lower than 1680x1050, which older models had. It's also lower than 2880x1800 found in a competitor model. It is also a TN display, not an IPS one.
I'm going to say "fine", as I've honestly never noticed an issue at all. I still do video editing on my desktop as it's way faster. I don't play games, so I can't answer that one for you.