Mozart has the most amazing location. A minute from Grand Place and two from the nearby parking garage it is the ideal spot to explore Brussels from. Unfortunately it is suffering from a need for maintenance, a lack of air-conditioning and a lack of cleanliness in the breakfast area.
Things are pretty basic, which you expect for the price. Besides the location though this hotel's appearance is it's biggest selling point. A strange mix of North African and Barroque styles it's either incredibly kitch or absolutely gorgeous, I couldn't quite decide (but loved it anyway!).
Overall I would recommend it for a couple of nights stay on a tighter budget, but step out for breakfast (lots of nearby places).