Anything that allows you to circumvent the global cooldown will get you banned, ie delayed keypresses.
Anything that smart targets will get you banned, ie anything that automatically selects targets.
Anything that automates will get you banned, ie unattended play (doesn't require you at the keyboard pressing keys)

Rule of thumb: one keypress = one action in game.
Rule of thumb two: anything you do with a 3rd party external tool must be possible to do in-game with macros

Jamba is a WoW addon, not an external application, and perfectly legit.