Need recommendations for business trip

I'm traveling to Philadelphia with coworkers this week and looking for recommendations for places to eat for lunch and dinner. Unfortunately, my coworkers are not adventurous - they prefer burgers, fish & chips and generally American cuisine. I think they'd also be willing to try BBQ and Mexican. I'm reaching out for help because if I have to eat burgers all week, I'd like them to be good quality. I'd love to find a few good mid-range restaurants in town. We're staying downtown but would be willing to travel a little for a special place. The only place I've found so far is the Blue Duck Sandwich Co., good choice?

Thank you so much for your help!