I am a local here in Vegas and I must say that I love this place. We stop in for a margarita every time we're near Mandalay. The 'Original' margarita is for sure the best margarita in town. Fresh lime juice squeezed right in front of you and tequila - none of that sugary sweet-and-sour mix.
Their food is excellent as well. The nachos are great and they have so many additional toppings to choose from. I've also had the tacos; they now consist of 4 tacos which you can mix and match, and the burrito, both good. They offer 20% off to locals, which is always appreciated. Overall, great food, good atmosphere, and excellent margaritas!