As Jamie says, they are right next door to each other, so if you're heading there, might as well go big. I did prefer Pat's. Curiously, Pat's tried to open a store in NYC and it was awful - so disappointing.
Me, I always preferred Abner's on Penn's campus to both Pat's and Geno's, but the last time I was there, it was under new management and had slipped a little. When I lived in Philly, the same folks that owned Abner's owned a place down on South Street (or thereabouts) called Jim's Steaks. It was the same as Abner's. Jim's would get my recommendation as to where to go now.
Tony Luke's looked pretty damn good on the Travel Channel show Man V Food, very similar to what Abner's was back in the 80s.
Hey Philly guys, is there a consensus cheese? I started with provolone, moved on to American, ended up at wiz...