Without a doubt, the Myers-Briggs Type Indicator is the most well know personality typing system in existence. And why not? It's been around a long time. The first of its kind. It's been used by the government (heck, it may still be being used by the government), especially the military, and corporations of all sizes. It's a good indicator of patterns of behavior.
As such, it can be a useful tool for writers when trying to develop Personalities for their books. And, yes, let's call them Personalities, because not all characters have personalities. Don't get me wrong, that's not always a bad thing; two-dimensional (even one-dimensional!) characters have their place, but they are hardly Personalities.
But there's a problem... Okay, actually, there are a lot of problems...
And I'm not going to tell you what they are unless you hop over to Indie Writers Monthly. You'll also find some solutions, or at least a solution. I suppose it depends upon how many problems you bring with you. At any rate, you should go check it out. You might learn something about yourself. Or learn something about learning something about yourself in the future. Definitely one of those.