Fish is a great interactive shell. I've been using it for some time now.
A few things I occasionally run into: You can't just paste somebodies setup instructions into your shell anymore (you can temporarily invoke bash for that though). And when writing setup instructions yourself, sh is still pretty much the standard. VirtualEnv generates an activate.fish out of the box - nice! I still occasionally type !grep by accident. And I do miss &&.
A few things I occasionally run into: You can't just paste somebodies setup instructions into your shell anymore (you can temporarily invoke bash for that though). And when writing setup instructions yourself, sh is still pretty much the standard. VirtualEnv generates an activate.fish out of the box - nice! I still occasionally type !grep by accident. And I do miss &&.