We used to use Apple Denistry but as you noted, he is very busy and can be difficult to get into especially during peak season. We were pleased with his work. We now use Joel Bocanegra who is on the third floor of the Angel Building. He does excellent work, is reasonable although not as cheap as some dentists down there, and usually not too difficult to get an appointment.
I understand the comment from Motorcycle Jack about not needing to get meds in Mexico because of Tricare coverage. We also have Tricare for meds so have little need for meds. But we don't have dental insurance. The price difference between procedures such as a root canal, bridge or crown in the states and in Progresso are huge. While price consideration is important, it is also essential to select a competent dentist. Hence the advice to get advice from folks that have gone that route.