I would like to report on my trip to Brussel during September which included both Brussels Marriott Hotel and the Renaissance Brussels Hotel.
I started with Renaissance: I got good weekend corporate rate deal (below 90EUR flexible cancelation). I booked deluxe room and was upgraded to club room which is 2 level up. I did mobile check-in and I am MR gold. The room is spacious and well decorated and overlooking the street. It is a quiet neighborhood so had no issue with the room location. The hotel location is off track and well suited for European parliament visitors thus low occupancy during the weekend. Among the hotel guest are crew of emirates and another European carrier.
Also I was offered breakfast in the main restaurant though when I show up, I was given a ticket to write name, room number and choice of continental breakfast or full American breakfast. I did the full breakfast and did not show up on my bill. (Mobile check-out)
The hotel parking is shared with the neighbor Marriott Executive Apartment and it cost me 10EUR for one night. Please activate the parking ticket from the reception if you are planning to go out of the parking during the day so that you are not charged the hourly rate every time.

The next day I moved to Brussels Marriott for one night. Before I do the mobile check-in one day earlier I noticed the room was changed from Deluxe to Junior Suite (3 level upgrade), was glad to see. When I arrived it turned-out to be even better, a corner suite overlooking Brussels Stock Exchange. I could not be happier. Keep in mind this is European suite, defiantly below 40 sqm. I did not experience any noise.
In addition, as MR gold we were offered a breakfast in the executive lounge or the main restaurant, we opted for restaurant because of the variety. Similar to Renaissance, I was given like a ticket with option to be ticked of continental breakfast or full American breakfast. I did the full breakfast (lovely one) and did not show up on my bill. (Mobile check-out).
The executive lounge is well staffed and it is in the ground floor next to the hotel entrance and overlooking the stock exchange building. During the evening, varieties of light meals were offered but we opted for diners in the city center.
As for the location, it is right in the city center where pedestrian area is. The only other option I had in mind is Hilton grand palace (HH gold), which was of similar price but I went with Marriott to complete the platinum challenge.