Paul
The demo was fine and all the components had their qualities.
In respect of the speakers I think the Radius were probably overall better with a wider soundstage and a touch more detail although they used the smaller sub (360). In saying that the Q7000 were new from the box so not run in yet and should only get better. From the demo it was a close call which, considering the price difference, I am leaning more towards the Q Acoustics. My ears could not detect a £500 improvement in sound between them.
On the receiver front the 609 had the edge on movie soundtracks but the 671 had it on music. As my first priority is music I will probably plump for the Yamaha.