Hi, i'm upgrading my speakers and cannot decide between these two.I have a arcam a65+ amp and a cambridge audio 640 v1. My room is 4.5mx3.5m leading to another room slightly smaller. Floorstanders or standmounts.
I wouldn't get too hung up on the standmounter vs floorstander debate. You just need to get the best speakers for your system/room/budget.
In your case I think the KEF iQ5SEs would work the best. They're less obtrusive and cheaper than the B&Ws (once the 685s are on stands), and would be a better match with your Arcam amp. Take a listen to the KEFs. I doubt you'll be disappointed.
I've had Arcam and B&W speakers for years and would never pair differently. The B&W speakers suit the Arcam amps so well. I've tried Kef with Arcam and didnt like them at all. Felt the sounded a little wooly and the bass didnt compare to B&W at all.
A good set of B&W standmount speakers with decent stands (Atacama SE24's have always been brilliant in my opinion) will sound just as good, if not better than floorstanders in the right room with the right amp.
The new 685's are great. Theyre responsive, crisp treble and great clarity in the midrange with lush deep bass thats not boomy but well controlled and well timed. Punchy!!!