The ability of being able use this service from anywhere within our hotel, even if you are traveling or at home! It has helped us in many ways but mostly it helps with customer satisfaction by giving them access when they need their room so we can keep more customers happy than ever before!! I think one thing people don't realize about OBM vs other sites like Hotelscombined etc.,is how easy everything works once set up correctly (i have used both).
We also love using email notifications as well because sometimes things get overlooked otherwise which would be helpful too.