My experience is the same as Chexfan's. I signed up, decided I like getting a paper statement, and changed back. My bonus miles remained in my account. They also have a program in which every time you email their service center with a non-mileage credit subject, you will get 500 bonus miles. I don't believe there is a limit to these, but I have only written one non-mileage related email to them. That might be why you got an additional 500 miles.