I love their wheat bread,  and I love that I can get sprouts and avocado on a sub.   

Four different iced teas (unsugared, sugared, sugared green, and raspberry i think) is nice too.   

The staff at this location always seems like they're having fun,  which may not necessarily make the sandwich taste better but makes the overall experience of buying lunch a bit more pleasant.     

Of the locally available chain sub shops (Subway, Blimpie, Port of Subs, Goodcents, Cousins, and I'm probably forgetting some..),  Silver Mine is easily my favorite.