This thread got me curious.

In a nutshell, what's your opinion on the typology systems that are out there? Which ones are more valid, practical, theoretically accurate, lacking.. ? What is the time and place for each?

In terms of the pure dichotomies (E/I, S/N, T/F, J/P), MBTI seems to be useful as a way for people to be aware of the fact that other people think differently than they do, possibly diving into the specifics of these differences. When applied correctly, one can be aware of their own mental filters and how better to communicate with others.

For the most part, it's simple enough to just work and doesn't attempt to explain too much. Much of what's wrong with it is what's read into it by other people.

To that end, extensions of the theory, including those that introduce roles for all eight functions (including the shadow functions), seem to try and fail to explain too much to be of much use.

That said, I'm a fan of Jack Flack's simpler MBTI variant.

More ambitious, possibly with a better description of the functions than MBTI.

For the most part, however, I file it under "Extensions to MBTI," where it tries to explain too much for little gain. Too much importance is placed on intertype relationships, which are too greatly affected by sociological factors to be accurately explained by such a system.

I'll take the function descriptions, but leave most of the rest of the system.

It seems as though the Enneagram does a better job than most systems of providing a holistic picture of personality, tying one's underlying vices (avarice, anxiety, anger..) to their behaviors.

This is one that I'm still exploring, though.

Some others that I might share on soon:
Big Five
Classic Temperaments

What do you think about these systems and others? Feel free to post any others that I've missed!