Had a very comfortable stay at John's & Ceca's apartment.
Very central location, close to metro and restaurants and a short walk to Grand Place. The apartment is large, quiet, and had several nice touches, such as tea, coffee and water available on arrival. Also, good central heating which was much appreciated on a rainy autumn weekend :)
The arrival and check out process is very convenient, and the hosts responded quickly to communications.
The only negative I would note is that even with an elevator, there are some stairs to climb to the apartment and some guests in other apartments had to struggle with baby buggies or luggage (other apartments in the building seem to also be holiday apartments).
Overall, for the space, amenities and price, I would highly recommend this apartment.