I switched to fish for about six months, and recently went back to zsh when I realised that the three things I really liked about it (abbreviations, syntax highlighting and autosuggestions) were all doable in zsh with extensions [0]. (It feels pretty slow, even slower than say OMZ, but that's not such a big deal for me.)
[0] https://github.com/olets/zsh-abbr
https://github.com/zsh-users/zsh-syntax-highlighting
https://github.com/zsh-users/zsh-autosuggestions