In my opinion the couple can talk about which one to take. If I had the choice I would take the last name that sounds best, I personally don't care about my last name but that's just me. I know some people can be uptight about that kind stuff.
The couple would have to make the choice about what is best for them. It's entirely possible that the women has more connection to the last name than the man does, in which case would have a harsher impact if the women would have to change if they want the same last name. It's overall the family's (By family I mean the husband and wife) choice who changes their last name.