Difference between Home sharing and Music sharing
http://support.apple.com/kb/HT2688?viewlocale=en_US
http://support.apple.com/kb/HT3819?viewlocale=en_US
With home sharing you play music from the pc or apple tv 2 or 3 on the iPhone, iPod or iPad using the native iPod/Music app (and not Remote app) so you have coverflow etc exactly as if the music was on the iPhone/iPod/iPad