I think it depends on the individual and the overall situation.
If a woman has followed the morg plan for a lifetime, she might not have much in her life except the church. That would make it harder for her.
A man might have trouble giving up the feelings of having priesthood power and leadership in God's kingdom. It might be especially hard for a man who has a hum-drum job and who gave up opportunities to go on a mission and marry young.
So many factors: BIC,convert, active, inactive, long heritage, none, male, female, kids, no kids, family dynamics,and on and on.
I think it's easier for men, for many reasons. Women tend to have a stronger emotional bond that keeps their testimony alive and have a lot more to lose at certain times of their life.
The environment makes a difference also. A strong heritage, and living in Mormon country as a BIC totally immersed in all of the traditions, etc, would make it more difficult, for men or women, I think.
It's easier if the whole family leaves together, I think.