I thought fish is the hot new thing
On the other hand, on my macOS there was a noticeable lag after I hit enter on a command that is not in bash. I also have very little attention span for figuring out fish's unique function loading system to pimp my shell like I would bash.
I'm a fish user, actually. That said, for those on zsh who want some of fish's most prominent user features without leaving, check out zsh-syntax-highlighting[1] and zsh-autosuggestions[2]. These are rather popular so long time users may not benefit from these suggestions.
[1] https://github.com/zsh-users/zsh-syntax-highlighting [2] https://github.com/zsh-users/zsh-autosuggestions