I've been using fish for over two years and love it. But the thing about fish is that is does totally break things that are expecting a sh/bash environment. There is more use out there and I've seen a number of shell tools/plugins include what to add to the fish config right under the bash and zsh sections (that's how I originally found out about fish).

Fish does have bugs though. I've seen enough stack traces while running early builds to question the security (although I'm sure we all remember the bash shell-shcok bug that was laying around for years).

If you haven't tried fish, I highly recommend it. It takes a little getting use to, but overall it adds a lot of really amazing functionality that I find really useful.