tried fish, went back to zsh
I'm all about ksh with PS1="$ " nowadays. Keeping it simple, minimal/no config. Same with editor, just nvi with 'set ru ai nu'
I'm way too much in love with good completion and history search. I also use differently coloured prompts to differentiate between machines and privileges.
Fish is great if you like the way it is doing things. The out-of-the-box config is really good. But I'm too much into little nitty-gritty details and so zsh it is.