I personally really dislike fish as an interactive shell as it's just so busy. Things keep popping up, everything is in so many different colours, etc. It's great if you like that sort of stuff, but I really appreciate a "quiet" environment. This is also why I use Vim: all the IDEs I tried are just so "busy".
I was only talking about scripting; I know fish scripting is different, but I have no idea if it's any good. For interactive shells I don't care what people use: it's 100% a personal choice.