My first and last experience at Casa Don Juan had to have been one of the absolute worst restaurant experiences I have ever had.
The overall atmosphere of the restaurant is unaccommodating and unwelcoming, and the staff treats you like trash if you ask for the simplest things. On top of their already overpriced dishes, charging $1.50 for a small spoonful of sour cream and accusing their customers of LYING when they receive the wrong order leads me to believe that the restaurant honestly doesn't care about their customers, and they are only out to leech money from them.
It would be much more worth your time and experience going to another fine Mexican restaurant in town like Bonito Michoacan on Decatur than to be harassed and provided with the lousy service at Casa Con Juan. It's a shame, really.