This hotel is in a very convenient place and is right by the train station which takes you to the Eurostar terminal.
Reception was too busy and it took a while to be checked in - the desk is too small and there were not enough staff to cope with the influx of people - and I was arriving late at night. This let the hotel down a bit.
The room I had was really comfortable, tastefully decorated with a pleasant enough view. The bathroom was comfortable and well designed.
I was attending a conference at the hotel and the food was delicious - beautiful buffet. Breakfast was good and the staff were attentive.

What a pleasant surprise: I booked this hotel more or less by mistake; I am glad I did.

Overall, this is the best hotel in Brussels I have stayed at so far, better than several more expensive and higher ranked hotels: Staff were very friendly throughout, special requests were readily accommodated, the room was large with two double beds, recently refurbished, well equipped and clean, and breakfast far above average. The only little flaws were the time it took staff to clear up the (larger part of the) restaurant after groups had enjoyed their breakfast (described in detail by other reviewers), and the limited number of English language TV channels (basically CNN and BBC World News).

The Mercure Brussels Center Louise almost felt like home from home after only a few days. I will be back (provided the price is right).

Great location just off Avenue Louise with its lovely shops and a few hops on the metro from the EU institutions, and there always seemed to be taxis outside if you needed them. Helpful as serves meals if you arrive late. Rooms fine and clean and sleep quality very good. I thoroughly enjoyed my 3 night stay and would definitely go back if the price was right as in Brussels, apart from the summer break you always need to shop around and book early if you want anything in the 100 euro bracket which is anywhere near the EU buildings or the centre.

The main attraction is the location, close to Louise Avenue. The Hotel has been renovated, at least partially, and our 6th floor privilege room had all the bearings of a four-star hotel: coffee/tea making facility, slippers, flat-screen TV, ample digital channels, space and an excellent bed (+ pillow).
The staff was courteous and multilingual, the breakfast was on the better side of good. All in all a very positive experience.