Anytime I have friends come to las Vegas I bring them here to GR BurGR. The burgers here are top notch, and I'd say I can't think of a better burger in Vegas.
The burgers are made from chopped up ribeye, so feel free to order the burger rare. The truffle fries are superb as well, and one order is more than enough for 2 people. The prices may seem a bit high, 13-18 for a burger, and 8-14 for apps and sides, but the quality and taste of the food definitely is in line with the prices.
There is a consistent line here, so be prepared for a little bit of a wait unless you're a Platinum or above member of Total Rewards.
In short, if you've never been here, you definitely have to give it a shot.