Based on your preference ATC is the far better choice. However many people prefer the BBC dip in the B&W midrange and the bass extension. The B&W is a more typical impressive sounding design that audiophiles would tend to go for over the precise sound of ATC. If you want to hear truth and a midrange that is a near to the clarity/transparency of the best electrostatics then go ATC. This midrange is used by Telarc and many others. You will enjoy it but your friends may remark on the lack of boom and sizzle. If you suspect a tendency yourself towards plenty of bass and scintillating highs and want a really cool looking speaker then B&W 805S is much more in tune with the "spices" that audiophiles tend to like the taste of.
