The study of temperament and personality is overall interesting and useful. I was actually glad when the forum name was changed to Typology Central, because it creates a broader scope. My understanding is that each of the systems I've read about has its limitations, but that doesn't mean there is nothing to be gained. MBTI, Enneagram, or anything else can be a useful starting point to see how others have thought about temperament and ways to distill core attributes and organize them into a system of categorization. I do think there are some categories in these systems that do reflect fundamental aspects of human thought and behavior, but there is probably a great deal more time and investigation needed to have a consistent and valid system. Having a forum where a mix of these can be compared and questioned is the ideal format for looking into this topic.