Me + Philly =

[Mockery]

Jim's > Geno's & Pat's. That's my opinion and I hope it incites a huge riot.

But if you insist on going to one of the other two more famous ones, I'd say go with Pat's, because they make the Philly cheesesteak the way it's supposed to be made: the meat is cut up ultra-thin and loaded heavily onto the bread, whereas Geno's just gives you longer uncut pieces of meat. It seriously makes a big difference in the whole cheesesteak experience. I'm not sure if Pat's offers a "double the beef" sandwich like Jim's does though. If they do, definitely go for that, because that's how I like 'em... extra beef and covered in pepper.