I have to say that my rating is not 100% objective because I have not stayed at the hotel. I booked and paid for a room 4 month in advance, but upon arrival, once receptionist confirmed with me that I intend to stay only one night and don't plan to come back after Ha Long Bay cruise, she informed me that the room they had reserved for us had some plumbing problems and they don't have any other rooms available. To rectify the problem they offered us to stay in Old Quarter Family Hotel which is a remodeled hostel and clearly lacks the charm of this hotel. Their selling point was that they are moving us to a bigger room that can accommodate 4 people (it was two of us) which is more expensive, but useless for us. I didn't want to waste my time searching for a new hotel and accepted the offer knowing that I will be moving to a worse hotel. My expectations proved to be correct and I was not happy with the new hotel (see my review of that property).
I could be wrong, but it seems to me they don't like to offer rooms for one night in a high season and use their other (cheaper) property to move some people.