The hotel is conveniently located if you're working for the EU Parliament, it's just a few steps away from the building. Other EU buildings are also within walking distance.
However, the hotel is a bit run-down, especially the bathrooms. I stay in this hotel quite frequently and quite often I have a problem with the shower hose that is broken off the hand shower so water is leaking. My other pet peeve is the lack of proper lighting. In fact, the hotel uses the weakest light bulbs available, so after dark, you won't be able to read a book, unless you bring your own reading light.
Since it is an apartment hotel, all rooms have a kitchenette, which is convenient for longer stays, but it also means that you'll smell what other guests are cooking.
The hotel provides access to a great fitness center WorldClass Gym, which is located on the premises.

A comfortable hotel with big rooms, good facilities, good location. The personal touch which you get in most of the Europe hotels, is missing though. Good for your stay while on business but I would love to stay in a smaller place with not so professional (and not so friendly) staffs when I am on holiday. They are pulling down a building just in front of the hotel now, so a little noisy and dusty now.

My friends and I (there were 10 of us), we stayed in two two-bedroom appartments. The appartments were very spacious and clean. Each of them had two bathrooms, fully-equipped kitchen and a living-room with the dinning table, sofa/bed (we used it for our 5th person) and a large plazma TV. The rooms were full of light as there were a lot of windows all around the appartment.
The service was also very good. The reception guy helped us with directions, gave the map of Brussels.
The hotel has a big underground parking (25 EUR for car per day as far as I remember).
The only dissadvantages were that there was no free internet in the hotel and the breakfast was not included (but it's the usual thing for the residence hotel).
The location is excellent. The hotel is near the Luxembourg station and right in from of the European Parliament. It took us around 20 minutes to get to the city center on foot.
We really enjoyed staying in this hotel.

I booked this hotel through Expedia just because I got a great rate on it. For a group of two couples staying in two bedrooms, your options are limited, so I was just happy to get anything matching that description on such short notice. We were apprehensive at the checkin because the desk was so unassuming, but we were we all really pleased when we entered the room itself. It was very large, probably one of the larger hotel rooms we got during our European trip, and it had two bedrooms, 1.5 bathrooms, and a full kitchen, which was an unexpected treat. The living room was large, and we could have easily slept two more people if needed there. There was also an accessible balcony, and the apartment was very clean and well-lit.

The only problems we did have were due to some street noise, but this was during the world cup, so I would imagine that every hotel had these problems around that time.