This place was fantastic, I would absolutely recommend it to anyone. Apartment was well furnished and spacious. Although I never met him personally, he was great with communications and helped us get settled in promptly. As other people have commented, the water pressure is low, but this did not present any major issues.
It is above a restaurant with outdoor seating, so if the windows are open, you could potentially hear people and music from downstairs. This did not bother us at all since Brussels is obviously a busy city.
All in all, we had a great stay at an awesome flat.