Defalco's is amazingly delicious. The trick to getting your lunch in a timely fashion is to call ahead. It's usually ready in about fifteen minutes and you get to skip the line (as pickups are a separate cashier).
The cheesesteaks are phenomenally sinful, whether you go with the beef or the chicken. I try to eat healthily, but even I will admit weakness when faced with Defalco's. I'd like to see you resist once you have tasted their heavenly precursor to a heart attack, err, cheesesteak.
Also, don't skip dessert. The cannoli is epic.
If you want to eat in, there are tables along the windows. The grocery also has a good selection of Italian dry goods if you want to do something crazy like cook at home.