I have been a zsh user for quite some time (before that tcsh and before that csh). I am quite happy with it, but was wondering if there are any compelling features of bash that do not exist in zsh. And conversely, are there zsh features which do not exist in bash. My current feel is that bash is better:

• If you are familiar with it already and don't want to learn new syntax.
• It is going to exist on most all *nix machines by default, whereas zsh may be an extra install.

Not trying to start a religious battle here, which is why I'm just looking for features which exist in only one of the shells.