I flew Virgin Express (Business Class) on Sabena code share BRU London.
Yes, it was like a sardine can. Nick is absolutely right. However, the service was very friendly, motivated staff. They served a snack and champagner. I belive, we did not get a seat assignment. You board and sit where you want, like in a bus.
I would fly them again - I liked the attitude of the staff, Bronson can be proud of them - maybe not in economy unless it's real cheap and the flight is not to long.