Comparing loudspeakers just encapsulates how difficult it is, ’placed optimally’ that in itself is difficult, in my domestic room there are only so many locations where I can position two pairs of loudspeakers, 8Cs and LS60s both offer adjustment for position, usually I place 8cs really close to the front wall as that offers headroom and cancellation advantages.
Matching level, tonally and in terms of timbre they are virtually identical, much less difference than between kiis and 8Cs but then you can adjust both kii and 8C to taste, in terms of pure sound quality.
I don’t have any ‘dinosaur’ passives to compare with but I have in the past and led me to the conclusion that they are just not bothering with compared to contemporary designs.
Imaging on the Kefs is pinpoint as was the 8351Bs but the 8Cs again almost indistinguishable and they are placed further apart, it really does come down to personal taste and how ou intend to use the speakers and with what.
Really exactly as
@Absolute states, I do think cardioid adds clarity in the (midrange) and perhaps coax for image.
For a larger room, greater listening distance and bass extension/weight I would recommend the 8Cs but if you want to connect your Tv or your kids want to bluetooth/airplay then the KEFs are so easy to use.
Harman shuffler and unsighted level matched …
Keith