[honeydew]

I have read they dont last and will go back to normal size once stopping.

I've read that as well but I don't believe it (or rather I don't want to haha). I think the longer you take it, the more permanent it will be. I really can't imagine taking it from years on end and going from for example an A cup to an E cup and then when you stop taking the pills, they just deflate slowly. I believe at least some will stay, especially if you've grown actual breast tissue and not just fat being positioned more to the breasts from the estrogen. 
I'm interested in hearing other people's stories and opinions though.