I recently had a photographer who had never accepted credit cards and wanted to get set up. He naturally went to his bank first because he knew they offered the service. He figured since he did his banking there and they are a large company, they could offer the best rates.
Unfortunately, in the credit card processing world, this is just the opposite. Banks typically offer higher rates than most independent processing companies. Banks have a lot of overhead to pay. Also, it is an add on service that banks offer. Your local branch does not handle the processing. It is outsourced to a processing company. Since the processor is dealing with your money, you want to make sure you have a personal relationship with your processor and also have a knowledgeable company that eats and breathes processing.
So, when you are looking for a processor, think twice about working with your bank. If you are currently working with your bank, you might want to look into a free consultation to see if you are getting the best deal possible.