1-For men, height is important.
2-With men, height is important.
Which of the above correspond to which of the below:
a-Men consider height (perhaps a woman's height) to be important
b-It is important whether a man is tall or not (perhaps in the eyes of women)
c-The sentence is ambiguous
I think both are ambiguous.
#1 suggests to me a, slightly revised - Men consider height (their own or that of others) to be important.
#2 is ambiguous.