I use a 32" 4K monitor (LG UltraFine 32UL950-W) directly in front (landscape), and an identical 32" 4K monitor to the right (portrait) off a rMBP 2016, which gives me the best of both worlds. (Both running Retina mode at logical 1900x1080.) The landscape monitor is for the usual tasks, and the portrait monitor for coding (100 visible code lines in 15pt Operator Mono in VScode). A fantastic combination.
If monitors were sold by MP like cameras, all this ‘resolution’ stuff would stop confusing buyers.