There's two things that made me switch from tmux to screen:
- persistence of layouts. Screen doesn't remember if you had a split view open, it always opens the current terminal in full screen.
- screen's default hotkey ^A clashes with ssh's escape key. Yes, these are configurable but having to re-populate the same config file is like a papercut every time to access a new system.
Defaults matter, especially if you work across many different systems (and from different customers). At some point, it just becomes easier to learn the defaults than to (over-)optimize to your ideal workflow.