when you buy the voice pack, its basiclaly a mic that connects to the plug in the back of the unit. it also comes with the steering wheel control.. I find myself using that control a lot.
you can control track skip, am/fm station skip or preset skip, volume up&down.
voice recognition is also helpful when you have addresses saved up, like when you want to drive to a spot on your address from wherever you are, you press the voice button on the steering wheel control, then say that saved address, it'll auto config the route.