Awesome space and we really enjoyed our stay. The proximity to the train station and everything in the heart of Brussels.
We just had one issue for the particular week we were there. It was Bright Brussels (unbeknownst to us) and one of the exhibits was in the Mont des Arts, just outside the apartment windows. There was loud music, repeating every 12 minutes for four hours every evening, and what I assume was a lot more street noise from the crowds. Fortunately we have noise canceling headphones! And on the plus side, we enjoyed all of the exhibits and were able to walk to everything.
This is NOT a complaint against the hosts and we did not lower our rating. Just pointing out that if you are considering staying here and might be bothered by the noise, check to see if it's Bright Brussels week first. :)
We would love to stay here again, even for the same event week.