I stayed for a weekend and it it made a great base to stay at. It'd be perfect for one or two people. Even though you go through a shared area when entering and exiting, the space affords a lot of privacy. The bathroom is very well kitted-out with a good shower and double sinks, just as the photos show (the photos give a really good idea about what to expect).
I walked from Gare du Midi and it took about half an hour. There are also decent tram and bus links that stop close by (e.g. N10 at night from the centre runs every half hour or so through the night), so even though it's not right in the centre, the location is just fine. I also had to travel to ULB and for that it was perfect (another 30 mins walk).
So overall, if you want an idea of what the space is like, look at the photos. It's a nice bedroom and bathroom, and Felipe was a great host.