My only complaint, but a significant one, was that the mattress was the softest ever I have slept, or at least attempted to sleep, on. Rather like a semi-inflated air bed, it meant that both of us had a really poor nights sleep. Perhaps there are people who like very soft mattresses, but I'm not one and I can't recall ever having this experience in any hotel before. Regrettably it would make me think twice about returning to Dixseptieme.
Its a beautiful building, very close to the Grand Place, the Galleries and all of the centre. Staff were very friendly and helpful and breakfast, whilst expensive, was of a very high standard. Our room was in the new part of the hotel, but was a suite with the lounge area and bathroom in the undercroft of the old building - very atmospheric.