Screen is discussed along with tmux in the [comparison section](https://github.com/shell-pool/shpool#tmux-and-gnu-screen) of the README. For most of the section I just say `tmux` because saying `tmux` or `screen` can get annoying and they have a very similar set of features.
I betrayed screen over a decade ago and switch to tmux, and have been immensely happy. I have a tremendous amount of love and appreciation for the venerable Screen, but realistically very few people use it anymore. I don't think it makes much sense to compare. For the few that do still use Screen, they pretty much know how it compares to tmux so the tmux compare is pretty applicable.
I'm a happy screen user. But tbh, the main benefit (to me) is default ctrl-a key binding, while tmux would require a config (which I actually think is great, that tmux politely doesn't conflict by default).
Ability to run `tmux <command>` in the terminal and have it affect the current tmux session was a huge feature for me. The other was actually being able to understand and write my config file. You can get somewhat far in Screen without writing any config, but I wanted some small tweaks to optimize my workflow. For example, a more vim-style way to navigate windows, easier splitting of panes, the new prompt on a pane split to be the current working directory of the pane I was on when I triggered the split, easy ability to swap the location of panes, etc. It's not prettified at all since I'm the only (intended) user, but my tmux.conf if it's helpful to anyone: https://gist.github.com/FreedomBen/9c52a6fa1543689798a8a42b6...
It doesn't actually require a config. You can set the binding on the command-line when you launch it. Anything you can represent in a config file with Tmux (set -g prefix C-o) can be expressed on the command-line.
Furthermore, in my opinion, both the defaults (C-a, C-b) are bad, as they conflict with default readline key bindings for cursor movement.
It is mentioned in the first paragraph of the README:
shpool is a service that enables session persistence by allowing the creation of named shell sessions owned by shpool so that the session is not lost if the connection drops. shpool can be thought of as a lighter weight alternative to tmux or GNU screen.
