The thing I liked about oh-my-zsh when I switched from another shell was that it provided a wide variety of pre-built "plugin" scripts for customizing the shell for various environments/tasks. It's worth a try to just get a tour of some features available in zsh, and have some examples to look at. I don't know enough about either bash or zsh to list out feature-by-feature differences, but if you want a practical, real-world tour of zsh, oh-my-zsh is a good place to start.