20% of INTPs are said to be "gifted" in intelligence, whereas 37% of INTJs are.
Yet some of the most crazy minds, overall, have been INTP. Socrates (the other one), Einstein, Charles Darwin, etc.
I know my bias and voted accordingly: INTP is the smartest of the two. I can only speak from personal experience, in which I usually obliterate INTJs. Usually. Not always. INTJs, at the very least, are more talented and balanced.
Their talents are enviable, and they can get laid.