Most of them are mediocre. Most burger places were mediocre, and then the American gastropub trend saw burgers being made nice as opposed to diner food or bar food. They could also charge more money because they were making nicer food.

Eventually a bunch of the mediocre places shifted to try to also be nice, but mostly just increased prices, changed decor, and started using the word aioli more than mayo. Oh, and pretzel buns on burgers that got taller without being bigger and are cumbersome to eat.

In the plus side, if you like a Swiss burger with a garlic aioli, a burger with a fried egg on it, or a burger with 2 pieces of bacon, a spicy BBQ sauce, and fried onion strings and you're in the mood for some fries with bits of peel on them and a garlic Parmesan butter, then you know exactly what they're going to put in from of you and exactly what it'll taste like.

Mediocre. Not bad, but definitely not the best you've ever had.