First off, I won't be surprised if someone comes along and gives me crap for saying this but I really don't care. I feel a good instructor will prepare his/her student to be able to go up with anybody and pass. I know its easier for both sides to know what you need to pass, but I see it as doing something half @ssed. Learn everything you can about what you will be doing will make you a better and safer pilot. Bottom line is its your money, its your choice. As for myself, I would probably choose the DPE I have gone with many times before. They know you and you feel comfortable with them. On the flip side, if you do a commercial career its a good idea to get used to flying with people you don't know and may not be comfortable with. In the end you will (should) know PT'S, and if you know them know what you are doing and are safe, you should pass. But then, this is just my thought.