Let's be honest - those 'famous' sandwiches aren't very good at all. 50 years ago, they were probably cutting edge; nowadays they are throw back, dull and boring. I'm sorry I just can't get excited about French fries and Cole slaw on a sandwich.
However it is Pittsburgh history and it definitely a large tourist trap, I can also why people go to the other locations to catch a game and have a beer. But with that being said if you are going here to try their sandwiches because some TV show told you they are the best - you will find that you have been lied to.
Go for the history, go to say you have done it, but don't go expecting an amazing gourmet sandwich experience.