We don't have Papa John's in Canada but we have Domino's. We also have a large Canadian pizza franchise in Ontario called http://www.pizzapizza.ca/PPLWeb/CommandServlet?command=screenscmd&screenID=homepage. I prefer it to almost anything besides Pizza Hut and specialty italian restaurants.
Whaa?? Papa Johns is EVERYWHERE here. Pizza Pizza though, is found Saskatchewan and farther East.\
My favorite though, is Pizza 73. Best selection and their roasted chicken, jalapenos, and salsa for sauce is to die for.
EDIT: Apparently Pizza Pizza is the bigger name for Pizza 73. lol I thought both websites looked similar.
EDIT2: And picking local pizzerias over larger chains can be good and bad. Alot seem to neglect any kind of food safety and I've seen lots shut down for health violations. But on the other hand, you'll find that one small place that should be on Diners Drive Ins and Dives. Like http://www.cocobrooks.com/