The main Brussels Hilton, in which I have recently stayed twice, is very convenient. Brussels kinda doesn't really have one single downtown area per se. I want to say the Hilton is on Ave Tante Louise, but at any rate, it is very close (2 blocks) to the subeay station and tolerably close to the main train station (maybe 2 kilometers; the cab ride was about $7 US). You can walk to the museums (Modern and Ancient Art [adjacent to each other], chocolate museum, beer museum), the Grand Place (again maybe 2 kilometers), the Royal Palace, the famous "pissing boy statue," and so forth. There is "adult entertainment" close by if you are so inclined, and lots of bars and restaurants (mostly mediocre IMHO) This hotel had good rates (about $90 US) and the staff were efficient but quite stuffy. The rooms are average and the lounge is good. The bar is OK and not too expensive by American standards. I did not (never do) eat in the restaurant.

Overall I recommend the hotel and would give it about a 7.5 or an 8 based on my experiences worldwide.