essentially the satellites on the 5500's are the same as the 680's. they look a whole lot cooler though. Sub is now 10" instead of the 8", but the bass is much more controlled, although on the out of the box settings it doesnt hit nearly as hard as the 680's. The control center has a better display, and responds on point now. Other than those minor things, its the same. They just look a whole lot cooler.