I was teetering between 3 and 4 stars, but the price is what sealed the deal for me to round down on this place.
If you find yourself in DTLV needing a quick bite to eat, Casa Don Juan will totally do it for you. This isn't authentic Mexican food; it's the super-fast Mexican-American style restaurant that can be found across the country. You know what I'm talking about -- the food tastes exactly how you think it will. And this isn't a slam at all -- sometimes I crave that stuff!
One thing to note that you can't find at every other Mexican place: handmade tamales! And they are delicious! Other things we tried were margaritas, queso, tacos, and beans and rice... all were totally fine. The service was super fast and friendly too.
I did think the price was a bit too high for such fast-style Mexican food. Then again, this is Vegas, so I shouldn't have been so surprised.