I made this exact same switch a few months ago! RMBP 15 to Thinkpad X1 Carbon + Arch Linux.

I've loved it but I do miss the trackpad (although I've adjusted my workflow to use physical buttons now + thinkpad's trackpad). I also miss the larger screen (15" was really nice).

Whenever I go back to my RMBP 15 for moving files over, I've noticed the display is still nicer for text. Even with installing some calibrated color profiles, I haven't been able to match the same perfection the RMBP 15 had. Is this something you ran into at all / how did you tweak?