Which name do you prefer - Mary or Maribeth?

I know both are kind of old-fashioned and not really trendy these days. I have a friend in her early 20s named Maribeth that doesn't really love her name and is thinking of just going by Mary. If you had to choose between Mary or Maribeth, which one would you go with? I personally like both and don't think there's anything wrong with her name - it suits her. But I guess I'm biased. What do you think of each of these names?