Happy user here. If you spend a lot of time in the shell fish is totally worth checking out.
Good points:
* Fish's completion sure saves a lot of typing
* `brew install fish` on osx
* Config in ~/.config/ rather than cluttering up the root of your homedir
* Can change many settings without needing to edit config directly - eg. `set -U fish_user_paths $fish_user_paths ~/path/name`
Bad / not intended for:
* It's not for scripting. Just use bash for that.
* I've found appending to env vars to be fiddly. Maybe I'm doing it wrong
* pyvenv's bin/activate.fish was broken for a long time (not fish's fault!)