B&W vs. Sonus Faber

I’d think they are comparable in terms of quality. Probably find just as many that prefer either one. 
With Mc I would definitely go BW not SF. Better pairing. 

They sound completely different, no?

From what I heard, B&W neutral to somewhat forward, SF neutral to slightly on dark side. YMMV


Depends what you like and what electronics you have to pair with. But I think these are two with markedly different sounds so I’d listen again if you are unsure

Of course individual components have a defined sound.  How could they not?  If one has listened to a particular component (say speakers) across a variety of systems (say with 3-4 different amps) and the sound tends to have similar characteristics, one can make some pretty meaningful conclusions about the component.

Otherwise, under the contrary assumption, one would be forced to purchase an entire system (and perhaps a room) each time something is changed.  Of course that is not realistic.