This is a really beautiful, perfectly located apartment. There were lots of things we enjoyed about the bright, spacious, modern place, not the least of which was the access to the city centre and all of the fun things to do in Brussels.
However, we wouldn't necessarily recommend the apartment for a group of 3-4 people. It is better meant for 1 person or a couple. The space is very open, without doors to the living room, kitchen or bedroom, so that limits privacy. Although the bedroom is around a corner and is secluded, the open shower is right next to the bed so if you are 3-4 people, you need to be comfortable with that arrangement.
There's also very weak/no wifi signal in the bedroom, so if you like to surf and snooze you will need to use your data connection.
Otherwise, as mentioned, we would really recommend this place for 1-2 people. There's lots to like and you will be very well informed and taken care of.