This is by far the best burger in Las Vegas. Unfortunately, I mostly don't eat meat anymore, but their cheesy Mushroom Burger is also very tasty and worth repeat visits. The Shack Stack (best pronounced in an exaggerated Chicago accent) is the ultimate. It stacks the regular Shack Burger together with the cheesy Mushroom Burger. I love how their buns are U-shaped so they captured all the drippings from your burger rather than letting them escape into your hand or onto your tray.
Their crinkle-cut fries are mediocre in my opinion. Similar to frozen stuff my mom would've heated up in the oven for us growing up.
Their order takers are always friendly and engaging, and the dining room attendants are always prompt and efficient. The decor is really unique and fun. We always take out of town guests here at least once per visit.