I own Sonus Faber Grand Piano Home speakers. They have the same tonal balance as the Concertos, with a slightly lower bass extension. This means the Concertos are great speakers.
My absolute worst match was the Sim Audio I-5.I really don't know what all the fuss is with this machine, looks nice but it's not very musical. It made the Sonus sound bright and thin,even in the midrange (and the Sonus, like most italian speakers are midrange champs) pretty awfull. Tried a Magnum Dynalab MD-208 receiver, ( with apparently a Sim Audio amp inside) - even worse ( the class A rating from Stereophile is a joke on this, maybe an ''B'' for value, but certainly not ''A'' for sound quality ).
A very nice match was is Electrocompaniet EC-3. Not bad is the Musical Fidelity A-300. Best yet is the Sonic Frontiers Power 2 and line 2 combo, but it's way too expensive !
The best solution so far: Any nice quality TUBE integrated, from the Audiomat Arpège to even these inexpensive antique Sound Lab integrateds...they make the Sonus Faber sing...Hope this helps !