Both the MMPI and PAI have their place, in my mind. If there is the potential for legal issues, I tend to prefer the MMPI due to the strong research background. For general client use, I like the PAI (administration time, client acceptability, reading comprehension, item development, etc.). I am not a fan of the MCMI at all. The psychometric properties are poor (PPP, construct validity, temporal stability). It has shown significant gender bias and overdiagnosis. I like Millon's conceptualization and description of personality disorders but not his assessment measures.