For me Big Mamma's is a little bit of a drive so I don't pass by here often. However from what I have experienced, I will continue going back for years.
There's many various options for burgers, and I would recommend (my favs) The Big Spice & The Big Mushroom (see below) though most of their menu items are pretty good. The flavour is there, and they got that beef bacon which I love so much.
The Big Spice (grilled jalapenos, spicy smoked sausage, melted monterey jack jalapeno, chipotle mayo, onions, pickles, lettuce, smoked spicy bbq sauce, hot banana peppers).
The Big Mushroom (sauteed mushrooms, melted smoked provolone cheese, smoked Canadian beef strips, sauteed red onions, lettuce, mayo).
One issue I have is that sometimes it can take a while to prepare the burgers so be prepared to wait; especially if it's busy. Though the restaurant (and booths) are fairly small, and the place can get quite busy, the food makes up for most shortfalls. Even the Classic burger is good (tip: if you want something simple but not boring, get a Classic burger with melted smoked provolone cheese and smoked beef strips added). And if you don't like it, get out of Big Mamma's House.