I stayed here in October for a business trip. The hotel was clean, spatious and has an (apparently redecorated) bar. It was actually exactly what I saw on their website so no surprises there. I wanted to post a review because at the day I was there, the Belgian airlines were on strike and the way the staff handled this situation was pretty surprising and positive.
I only stayed for one night and didn't get the time to check everything out, but for me it was ok.

Fortunately I had ordered a European chip for our GPS, Gertie, and she got us out of the airport and through the highway turnoffs without mishap. Finding the entrance to the hotel however was not an easy task. The hotel is about 30 minutes east northeast of Brussels. Leuven is a maze of one way streets with long names you cannot possibly pronounce. We finally spot the hotel and after 4 or 5 circles come on the right series of one way roads to our destination. Though there is plenty of parking, you pay for it which doesn't seem right for a '4 star' hotel.

It is now about 11:30 local time (5:30am body time) when we arrive and fortunately our room is ready and our Internet package delivered by the local Tourist Board. I found a package that included 2 night’s hotel, a 3 course beer dinner, several beer samplings and a beer/food pairing. In our welcome kit was also a 4-pack sample of Leffe Beers (Blonde, Bruin, Tripel and 9% along with appropriate glassware), tourist information brochures, and a local map.

The hotel was quiet and the room adequate but I failed to see why it was rated 4 star as the room was on the small side and there was no coffee maker in the room.

Breakfast buffet was included in our package and it was 4 star. All kinds of meats, fresh breads, yogurts, cereals, waffles, and even a chocolate fountain and champagne for mimosas. The breakfast room overlooks the lovely gardens that surround the hotel with nice groups of outdoor seating to enjoy the green space.

Stayed at the Begijnhof Congres Hotel in January 2010 for two nights. We had meetings in the nearby Faculty Club so the location was very convenient.
The hotel itself has a nice reception and bar area, the operating hours are short i.e. you can't get lunch in the bar until after 2pm.
The staff are nice but €25 for breakfast considering what the limited choice on offer is expensive.
The rooms would be my biggest gripe, the beds and pillows are uncomfortable and you can hear the noise from the first floor all too easily. I'd get over the other problems if the room was comfortable but its not.

Hotel: Relaxed business conference hotel at the edge of Leuven. Tasteful class, with exposed brick hallways and rather spacious rooms and bathrooms. Bar in lobby, including a free "welcome drink". (as long as you don't arrive too late in the evening, as I did.)
Room: Average, though rather spacious for European standards.
Location: On the edge of the town center, yet close enough for a short 7-10min walk to the central bar-lined square.
Staff: Professional and friendly, above average.