OK, I HAVE to comment here because
Grace is my mn and
Jane is my sister's! We are
Julia Grace and
Laura Jane.
I like them both but would go with
Jane for naming a child now because
Grace has become quite popular. But I don't know if that's the reason you are considering the names. Otherwise, I just get a different feeling from each one -- but considering how close I am to the names I can't really give an opinion . . .