I know someone who got out of Scientology years ago and was declared a "suppressive personality" by them. Any Scientologist who was supposedly her friend shunned her. Scientologists would come to her door and intimidate her. It was ugly. She had to go through therapy to get through it. She said it is a cult. They drain your money, and as you get to higher levels, they slowly get you to believe more and more nutty things. Their "auditing" is like a confessional, but they record it. So when you try to leave, they use what you told them in private against you. Knowing what I know from her, I would never, ever join them.
My experience wasn't anywhere near as bad.