There is nothing wrong with Diego, but there's nothing that really sets it apart, either.
The service was friendly, and they bring you chips and salsa right away, always a plus. The salsa was smoky and had some heat that sneaks up on you.
Chicken empanadas for a starter; tasty, moist chicken on a bed of guacamole. Not a huge portion, so you may want to get multiple apps if you're really hungry.
Chili Colorado and Pollo Mole for dinner, both were prepared and presented nicely, and no complaints about the flavors, but like everything on the menu they're things I can get just about anywhere.
We shared a pitcher of sangria, which was excellent, and we skipped dessert.
There aren't too many great Mexican places in Vegas, so it's a bit of a shame to see this place get right to edge of being great and not quite get there.
PS: three stars to me is a good restaurant.