I wouldn't recommend it to anyone over the age of, say, 25. By that point you've done too many fucked up things and had too many fucked up things done to you to enjoy it with the clean slate you need. I think it can be really great developmentally for younger people, as it encourages you to think in shades of grey, not black and white. As has already been stated, not for people with any inclination toward mental health issues.