I certainly can recommend the Quatros. I used Quatros for a number of years in my 11.5' x 15' room, and I found them to be stellar, only selling them to move on to TAD CR-1's (it took a rather great speaker to displace them). I ran them with a couple different tube amps at 70W (EAR) and 100W (VAC), and they sang beautifully. Any owner of them must take the time to really dial them into the room, and if you do you can get fantastic results due to their tunable subwoofers. I listen to just about every type of music, and they delivered across the board.
This is only an endorsement of the value of the Vandersteens, as I am not familiar with the Sonus Fabers.
This is only an endorsement of the value of the Vandersteens, as I am not familiar with the Sonus Fabers.