Unfortunately, this really wasn't the best experience. First of all, they will ask you for a €100 deposit, which violates AirBnB's terms of use. Second of all, it's actually a company running it; I never actually met the "hosts." Finally, the room we reserved was not the room we were given.
It wasn't all bad though, the location near Gare du Midi was very convenient. It's not the best part of town, but it's not too bad either. The wifi was very fast and reliable. There was also a lift which was great with our heavy bags.
I probably wouldn't stay with these hosts again. They seem to go against the spirit of AirBnB and advertising one room and pricing a different room is very bad practice.
There are many choices in Brussels. I would suggest using someone else.