Peony,
I haven't had any experience with mediums or fortune tellers, I asked the same question once on this site to see what evidence there was out there for the spirit world.
I found insufficient evidence. My niece goes to a fortune teller and I asked her if she was told her destiny was something negative would she try and pursue a different course to ensure a positive outcome. Her answer was she always had positive readings so there was no need to consider that question.
I thought this was very shortsighted of her. I can't quite see the purpose of trying to find out what the future holds, I believe through hard work and determination we make our own future, and some of it is out of our control which we just have to deal with and accept.
Kate xx