As far as Brussels hotels are concerned, the Chantecler falls in the cheap category, so it's an option if you are in a tight budget. The location in the lower town is indeed quite convenient, there are many shops, cafes and bars around, the Grand Place is a few blocks away, the Bourse metro station is two blocks away and you can walk to and from the Central station in around 10 minutes (from is easier than to, it's downhill).
I stayed in one of the back rooms, which means no noise from other rooms or the bar across the street, but with a view to a ventilation shaft. The room was very badly lit and rather small for a twin, unlike the bathroom which was actually quite large. The room looks outdated and a bit worn, but it looked and smelled clean (too much disinfectant). The breakfast (included in the price) consisted of bread rolls that you got yourself from a plastic bag, marmelade, butter, juice, milk and coffee.
Oddly, you have to pay up front for the room, and it seems as if the hotel gets walk in customers (there is a large sign with the prices outside and photos of the rooms at the entrance). The staff seems disinterested, but when asked for information they are quite helpful and all spoke good english.
On the other hand, this is not the only cheap hotel in the area, but in late March 2007 this was the only one available, so I gave it a try. Having been to other nearby hotels in the past, I would not go back to that one again, you can certainly do better for the same money if you book a bit more in advance.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC