The hamburger is just that: a potato bun and a slim burger patty, with the option to add lettuce, tomato, and Shack Sauce free of charge.

Shake Shack is at its best when given creative freedom. The burger patty is excellently meaty, and the bun soft and doughy, but the hamburger falls a little flat without toppings.

Despite its low position, the Veggie Shack is worth knowing about. The patty is a blend of healthy ingredients, topped with fried onions, pickles, and Shack Sauce.

Unfortunately, the patty tastes like the ingredients that it's made from, leading to an earthy-tasting burger. At nearly $9, this burger might not be worth the splurge.

The Shack Stack is a mashup of two great menu items, the Shackburger and the 'Shroom Burger, piled on top of each other and smashed between buns.

However, the burger and the portobello overpower each other, taking away from the other what makes them each great. It's also one of the most expensive items on the menu.

While the Shack Stack's issue is being overindulgent, the black truffle gives it a surprising flavor that allows the burger and the mushroom to shine.

This limited-time burger ranks low for its overwhelming build, but you should choose the Black Truffle Shack Stack over the regular Stack.

The Black Truffle Burger is similar to the Black Truffle Shack Stack, but it's topped with crispy fried onions instead of the cheese-stuffed mushroom.

That makes this limited-time burger less overwhelming physically while maintaining its strong flavor. It's a heavy, salty, overly rich burger, but worth a try.