I judge my lunch and dinner places to a different set of criteria. For lunch it's about convenience, cost, and taste. A distant fourth criterion might be the relative nutritional value of the meal. Firehouse, wins on the first three and is worthy of inclusion into the lunch time rotation.
The sandwiches are hearty, heavy, and tasty. Denser and more robust flavors then you'd get at the chain sub spots. I doubt that this place will win any accolades from the American Heart Association but I also doubt that 85% percent of its patrons even consider calorie counts when they order one of these sandwiches.
A great sub. Just make sure you eat fruits, vegetables, and other healthy options when you're not here.