One of my friends used it. And she just got out of the hospital because she had a blood clot in her brain. But she was stupid and smoked on it. Besides that, nothing bad happened.
I'm of the impression that Yaz has had a lot of legal actions and safety issues. But then again, I think nearly all birth control has serious risks. If I were in your position, there's no way I'd take it, but then I rarely even take aspirin or Tylenol or ibuprofen. Hopefully KB will offer a more informed opinion
The question is, "What is the reason for switching to Yaz?". And are you on BCP for contraception or difficult/irregular periods?