Used the #fish shell for a while. The 'live suggestions' feature is neat but not all that useful in practice IMO. The non-bash-compatible syntax is a bummer, as is the lack of incremental history search.
It did strike me how much faster it starts up compared to #zsh (with oh-my-zsh) - perhaps immaterial but 'feels nice'.
In search of the 'best of both worlds', I'm now using zsh without oh-my-zsh, but with the agnoster theme (which needed a small tweak as described at https://github.com/agnoster/agnoster-zsh-theme/issues/144).