I too am looking for smooth set and I've heard B&W 684 with Marantz pm 6004:
Only my impressions with my old B&W and B&W 684 in store (rock and Jazz):
Yam AS 500: very open sound , great horizontal image stage, but with too present high freq., for me; bass good only with loudness in, not very ergonomic remote and front commands;
Nad 316: good bass, but not at low volume; medium-high freq. a little bit confuse; very ergonomic and nice.
Marantz 6004: more liquid and natural medium freq.; bass enough, but you can add something at low volume with loudness, not possible with Nad; built like a tank in Japan, with golden input/output, smart and nice remote, that I found can drive my 20 years old CD Philips too!