The stay at Simon's apartment was very good. A short walk from the city centre or other hotspots. Handy car park.
The downside of it was the relative noise due to the road works and the school entrance in front, the horrific traffic jams if you use a car, and the weird bleach odour from the tap water/shower. This is Brussels!
Nothing to see with the apartment itself, and I do fairly advise it for anyone looking at a very good place for a short or long term stay in Brussels. The Grand Place, the instruments museum, royal park, Louise area, tube/bus/tram stations are all at short walk distance.