A complaint that I have heard about a majority of Story Games is that, unlike traditional roleplaying games, they are not designed to be enjoyed over a long period of repeat play, i.e. a campaign.
I know that PTA is best played as a campaign situation, but are there other story games that can stand up to repeat play over a long period of time? If so, what gives them such a high replay factor? What about it keeps bringing you back to the table with a smile on your face as you look forward to playing it again?
In the case of PTA, I would say its appeal is to watch the personal plots of the characters play out as the series progresses, and how those plots change the characters.