I tried using ZSH. My first experience was using a bunch of plugins like zsh spaceship and having the shell slow to a complete halt.

I then used "stock zsh" and running commands was fine except some autocompletes like git-autocomplete were terribly slow and, for example, did not support `git switch`. This broke my workflow and it was easier to just go back to bash than to figure out how zsh works. I found that autocomplete in zsh is a lot more opaque than in bash. I'm sure there are ways to fix it. My way was to switch to bash.

(Now I use magit so the need is lessened.)