I have also used the jailbreak.
The guys from customtronix are a great bunch and the support is more than excellent.
The jb allows you to use the uconnect search functions while driving; bluray on the main screen while driving, on some models it adds the SRT Menu and most of the functions (my fav appls). You can add cameras and other stuff now as well. Judt visit their site and have a good read.
It does NOT make your car faster or safe more fuel.