Opinion is divided, but I think it can be quite revealing. I would say it is worth a look, and can be fun even if you disagree with the final assessment. There are many tests available for free, a good one is
here.
Obviously it's a big approximation as it is splitting the whole variety of human personalities into 16 types, but it is used quite a lot in business (everyone in my office had to do it) and is I think very broadly correct.
I always come out as INTJ, by the way. I would assume that INTJ is disproportionately over-represented in this forum, certainly more than 1/16 = 6.25%.
