I arrived a little later than anticipated (around 10 pm), but I always thought Brussels was relatively safe. I quickly changed my mind walking the short distance from Brussel-North to the hotel. Do not plan on being outside at night, especially alone.
The staff was friendly, but the room had been cheaply/poorly updated. I didn't expect a really fancy room and simply needed a pre-flight hotel, but it felt dingy. There were holes and stains on the hallway/bathroom walls and what looked like mold all around the tub.
If you want somewhere cheap and only plan to walk to/from during the day it could be ok, but otherwise I won't be back.