I haven't heard the DM603 S2 but I'll go hear them soon just cause it's fun ...well I'm always shopping too

and I can hear them within the lunch time window of work.
But IMO that slight bright character you mention has been characteristic of most B&W's for as long as I've been listening to them, over 30 years. In the cases I've heard, I usually like it but then conclude I don't want to live with it. So I go for something that might be a different kind of distortion but is more generally pleasing to me.
shshshshh, hear the space, the sounds of silence: