I never knew bananas and figs to be even remotely similar, except perhaps in the fact that though both are fruit, neither is particularly "juicy" but rather mushy and moist.
I've always liked both equally and wouldn't consider one over another as a matter of preference. I never paired them against each other. I will say, however, that I was advised in my last pregnancy by my midwife to eat figs in the final trimester to aid labor, prime the cervix, and possibly bring on a quicker labor. My final baby (out of 4) did come a week early, and it was a wonderfully easy delivery. (Could also be that she was #4...)
Anyway, it was definitely a FIG recommendation and not a banana rec, so I'm guessing they do not work equally in the nutrition department.