I am no expert on mexican or tacos but this place is significantly better than rancho grande and would be my first choice for a mexican meal in south beach. It is also lighter than rancho grande so you can probably eat there more often.
I recommend the tacos, they were very good, their tortillas are homemade btw.
I did not love the signature app of the grilled cheese log though but it was ok (I love almost anything with cheese btw so let this be a warning that I just thought it was ok).
I also recommend their signature dessert which is also homemade. It is sweet cheese in a tortilla with strawberry sauce. I really enjoyed it.
BTW you can walk through the 701 building on lincoln rd and you will see it on the other side. They also said they will start delivery in about a month for those who are interested.