If you use console a lot ( or not that much) you simply have to install this nice tool . Ton's of plugins and themes, very nice and helpful autocomplete for bunch of applications and services :
- and so on so on
If you still thing wheather you need it or not - stop thinkign and just install it with one easy command :
curl -L http://install.ohmyz.sh | sh
Alternative ways of installation you can find here
To make zsh a default console you need to write :
chsh -s /bin/zsh
I'm a mac user, so if this commands doesn't work on your machine then i'm pretty sure that you can find how to set it up properly on your machine in Google.