I was told by a sales person in an audio store that 720 p is better quality than 1080i because 1080i represents approximately 520P.. is that true ? I know 1080p is the max and best, but between 720p and 1080i which resolution gives the better picture quality ?

thanks

Acoustic Zen Adagio, Veritas center, Axiom EP500, QS8s, Anthem AVM20, MC20,Adcom GFA7400