Scion TC stereo question?

Im getting a scion tc and am fiddling with all the options. The premium stereo option plagues me. Its the same thing? Just looks different, and adds the cool little effect thingy right? Why would i spend 400 bucks on this lol...(why am i considering it is the real question hah)..is there any other differences? and, should i go for the upgraded premium system?