One of the arguments that I heard from time to time in comparing 720p and 1080i was that 720p handled fast motion on the screen slightly better. I am not sure that was ever the case but perhaps someone out there who has made that visual comparison could comment. Either way, with normal viewing, the differences between the two are negligible.
Once again, unfortunately, you ran into another retail A/V electronics (so-called) salesperson who didn't have a clue what they were talking about. The stores are full of them.
