First off, the people giving Valle Luna five stars are bonkers. This is a mediocre Mexican restaurant that serves exactly what you'd expect -- watered down margaritas and things in tortillas smothered in cheese.
This isn't necessarily a bad thing. I have known people who can eat this type of food all day, every day and not get tired of it. Heck, they might even go on Yelp and give it a coveted five-star. Not this guy.
If you're in Arizona and you've never had Mexican food for some reason, I certainly wouldn't start here. There are five-star deserving hole-in-the-wall type restaurants LITTERED all over the valley with names even more Spanish-sounding than Valle Luna.
However, if you are the type that enjoys a good Macayo's enchilada, or the margarita mix out of the big plastic bottle--give Valle Luna a try.