I'm afraid that Peter's is really overrated. There's nothing special about the food, although the location is convenient and it's nice to sit and eat in the parking lot on a summer's night. When I first moved to Calgary 15 years ago, people raved about it, and I found it didn't live up to the ravings. I guess I don't have the childhood memories to go with it :-) The staff is quick and efficient, although the washrooms are a little dodgy.
If I want a good burger, I'd rather drive to Edmonton for Red Robin's or go nearby to Boogie's Burgers. Tommy's Burger Bar is also a better choice.