I listened to them briefly at Boenicke's Basel studio last Christmas time.
Set well away from the walls, in a fairly large listening space and with the Boenicke subwoofer in the mix they sounded open and spacious, voluminous bass with good "off axis response" pretty much as advertised, (I suppose that means they're not that directional and you don't have to position yourself in a static sweet spot?).
I have a pair of SLS which exhibit similar characteristics and like them a lot, but they do need a bit of room around them to sound at their best, and don't like being sat in the corners. The ability to play around with the bass on the SLS is a bonus in this respect.
The W5's I listened to were powered by a Cary SEi 300b integrated, fed by an M2Tech DAC from Apple laptop which seemed a well balanced system with a pretty small footprint so I imagine ideal for the usual London shoebox sized flat...