for me 1080p is fine, I dont have that big of a tv, my concern is just storage space and my laziness. If I cared a bit more I would probably setup a second instance of Radarr to do 4k for my personal viewing, or if I didnt share my library with my family and friends. With 4k comes other issues you normally dont see when streaming since streaming services transcode down the move the bit rate is a lot lower and you dont see any issues, but when streaming locally the bit rate can go well over 100mbit and most tv's dont have over 100mbit connection, so you need something like an nvidia shield or xbox to not have stuttering, but it does look really nice seeing clear blacks instead of the blocks you get when watching something from like prime video. its comparable to playing the bluray if you have the right setup and file.

I prefer to do 1080p mainly because I share my library with friends and family and let them request whatever they want, their requests are automatically approved and pulled so my storage space is important, for example someone requested the office, thats like 560gb right there, but I really liked the show chernobyl so I pulled that at 4k and its only 5 episodes and thats already 140gb