Ive been to Vegas twice and both visits Ive went to Tacos El Gordo. The first time was as mind blowing as the next. I enjoyed every single part of the meal. Upon arrival you'll probably get hit by several lines and be confused af, ask one of the staff to explain each of the lines to you so you can line up according, sometimes they can get other things from other lines for you if it isn't too busy. When youre done picking and choosing all the tacos, (seriously get ALL OF THEM!) as well as a order of fries (half portion is enough for 2) get in the cashier line and pay the lady! it might be hard to find a seat sometimes especially if you're visiting on a busy weekend.
The service is very fast-food but everyone is very friendly and will engage in conversation if you want. its as authentic as it gets.
The price is cheap but it surely does not affect the quality of the food. I had tacos in New York at the Chelsea Market and it was 3.99 EACH taco, for less than half of that Tacos EL Gordo has you beat ;)
The location was very easy to find there is also parking for those who chose to drive. Its also walking distance from the Wynn-Encore hotel!
This has became a Vegas-Must for me personally every time I come, my visits were 3 years apart but the quality hasnt seemed to have changed whatsoever,