I like Subway, on occasion. The bread is only adequate and the meats and cheeses are sliced paper thin and portioned out in tiny amounts. It's the veggie selection that make the sandwiches worthwhile. I always get double meat and load it up with a ton of raw vegetables. The cheese is sliced so thin and is so meager that if you ordered quadruple cheese, I still don't think you could taste it, so isn't worth bothering with extra.
As to other sub shops, the one I get the biggest kick out of is Jimmy Johns. If you were to take an inventory of food items they stock in a store, I doubt that it would exceed a count of thirty, including the different chips and the soda syrups. They have _one_ type of cheese: provolone. Imagine opening a sandwich or sub shop that isn't a franchise and offering exactly one type of cheese... you'd be laughed out of business. They offer virtually no veggies beyond lettuce, tomato, onion and optional peppers. Still, they're inexpensive, they have pretty good bread and they're fresh. You can do worse.