Right on Music Valley Dr where you are staying, are 2 other campgrounds....we have stayed twice at Two Rivers, right next door to the KOA. It's smaller, but family run. There is also the Nashville RV resort on the same street.
I'd say that any of the 3, which includes the KOA you choose, is a fine choice. We too liked the central and yet easy in/out location. Personally, we like more open spaces but for camping inside Nashville, the 3 on Music Valley Dr can't be beat.