I have been eating here for more than 5 years. The food at Dona Maria is consistent and overall very good. There is plenty of seating and wait times are generally very short (less than 5 minutes). They make their tortillas on-site, the quality of the ingredients is better than you get in chain restaurants.
The issues we have regularly are:
Uncomfortable booths. Some of the booths have just aged and are no longer comfortable.
Slow service when busy. When they are busy your server will often disappear for a lot longer than we would like. They do have a good bus staff so your drinks and salsa do stayed filled. But if you want to order food it can be extremely annoying.
When sitting on the South side of the building the ambient noise can get very loud.
If you don't mind dinner taking 75 minutes this place is fantastic.