Not a graduate, but I met one of the founders of Postling at PR Camp last year and he spoke very highly of the program. It was a while ago, but I think he was saying that compared to YC there was more of a focus on business advice, and there were more contact hours with the mentors. I'm not sure to what extent that is true, but it certainly seems like a quality program that was run this way would be useful to some founders. Obviously different founders have different levels of experience and skills, so there probably isn't one best model, at least from the perspective of the founders.