I have had someone sing the praises of zsh, tried it, was like "that isn't so much better than bash" and went back. Then I heard about oh-my-zsh, tried zsh with oh-my-zsh, and stayed. I still think it's not a big deal, but it is an improvement.
I'm pretty much in the same boat. Heck, once I learned that BSD's /bin/sh gives you history (and I think filename completion?) I switched to that when I'm on BSD (I don't feel strongly enough about it on Lnux, which often uses dash and is more of a headache).
Then again, I don't do much with the shell per se (not writing scripts or any thing like that).
