The Sacher has more history than other hotels in Vienna but because of its famous sacher torte it can also be overrun with tourists in the same way as Raffles in Singapore. In my experience, entry level at these grande dame hotels can be terribly disappointing so it's often best to seek out a boutique hotel, probably one without a restaurant, and choose the top rooms. In other words, avoid these big 'international' hotels beloved by travel agents and tour groups.