I've gone full circle with MBTI - from gleefully embracing the revelation that I'm an INTJ, to joining a message board dedicated to that type, to becoming its moderator, to quitting it after seeing too much infighting and too little progress (I was known as Night Runner, in case any other expats are here), to accepting it all as something that may have some validity for some people but, like most good things, is overrun by overly enthusiastic dummies. (I've kept my penchant for run-on sentences, though.)
Scientists will always mock MBTI because it's a self-reporting system. Very few are honest with themselves. Fewer yet can accept the results of their honesty. Or, to quote a horrible movie whose only redeeming quality may be this quote, "It's more of a guideline, anyway." ;)
(That didn't stop me from getting the "INTJ" license plate - still can't believe it was available!)