Personally I always choose Male (helps me meld with my char more)
But based on what i've heard it kinda goes like this:
Male: Arrogant and his put-downs seem the funniest
Female: Calm and she seems to be the more realistic inquisitor type
Also being good as a male sounds weird unless its just a passive goodness. Females could be either and it sounds perfect either way.
Assassins, having spent so much time sneaking around, are bound to have a sort of mix of Darth Jadus' trickery + Darth Baras' contacts. Not to mention that they would have a easier time of subtly manipulating certain things.
Just my two cents.