This was a great place for our trip to Brussels, and I can't really fault the flat itself. It was modern, quiet, clean and spacious, and we really liked having a kitchen which you obviously don't get in a hotel. The staff at the office (located about 6-7 minutes from the flat) were friendly and helpful. Unfortunately we were a bit unnerved by the location - it's very central which is great - but it felt a bit rundown and we didn't feel comfortable. To be fair, it wasn't just this area that we found to be a bit rough, many of the tourist streets in the centre of Brussels had the same feeling.
I'd definitely recommend the apartment if it were in a different area.