http://www.mayoclinic.com/health/mangosteen/an01197

this is from the mayo clinic web page and actually has some nice things to say about the mangosteen juice. not that it can cure or even relly help anything, but they do say its a nice rich source of antioxidents.and that it does seem to have some natural chemical that works as an anti inflamitory agent. so... it cant be all bad. but how does it taste?
im sure your going to find the staunch followers,just like with anything else. but like you i couldnt find any information that didnt come from somebody selling the juice or selling a competing product