big 5 is made to be accurate in statistics and is good at predicting some stuff, thats why its used in research the most(research is always based on some statistics) and thus has the most empirical evidence for it and thus its easiest to get funds for a study using big 5 than for MBTI.
MBTI on the other hand is much used, and also much misused and thus has a bad reputation in the research field(there are also much more stuff for its bad reputation in high academic circles, but it still has a good reputation in some areas, like career counseling).
Personally i think that MBTI/jungian typology looks things from deeper than big 5(and i like it better), but that kinda comes from the fact that big 5 is a trait theory and jungian typology tries to explain on what sort of mental processes the traits originate from. Also big 5 uses quite traits that correlate quite well with MBTI scales, so understanding both can benefit on understanding yourself and others. Naturally neither of the systems shows the whole of human nature, they just show it from a bit different angle.