I am continually interviewing good vets. I would go into each office prior to the appt, ask for a tour and ask about the doctor's credentials and awards and ask about his/her experience and training with small toy dogs especially yorkies.
If you can find a vet who owns yorkies that is the ultimate. I feel like a vet associated with a large veterinary practice like Banfield may be new and just out of school and not very experienced, but that is probably a generalization.
I have never used a Banfield vet and I am sure they are "told" by their corporate office what their protocols and philosophies have to be and they do not have the freedon that a vet with a privately owned practice might have.
Just my thoughts for what they are worth.