As other posters have mentioned, these are great services, and I use anytime I travel in Japan. I have never had a problem, and they are not very expensive. Still, since the OP mentions Narita to Tokyo, I agree with Ninja138. It really depends on where she is staying, and how close it is to the Airport Bus Stop,Tokyo Station or Ueno Station. On the N'EX, or the Skyliner plenty of people have luggage with them, and it is not a big deal. But other lines in Tokyo, it is pain to have big luggage with you. Thus, depending on the hotel location the luggage services can be really good.