My current setup:
5 Bowers and Wilkins M-1's (64hz-23khz +-3db)
SVS pb-1000 subwoofer (19-270hz +-3db)
Pioneer SC-1222k Class D Amp (120WPC/600Watt Total Output)
Room size 4400 cubic feet
I had my M1's for 3 months and unfortunately I returned them as faulty.
They had a good sound as front speakers in a 5.1 system but the build quality was poor. The special connectors that connected the speaker body to the base failed. One speaker had an intermittent connection, you would pick up the speaker to move it and it would stop working. The other speaker stopped working as the little metal clip inside the base had broken off as it looks like it had been poorly built/aligned to the body pin.
The B&W dealer was superb and took the speakers back without question. I got a full credit refund and upgraded to some B&W 686 bookshelf speakers with the normal cable connectors. I just added some gold banana plugs to my 14AWG cable and they are perfect. The 686 are much better speakers - excellent bass response, better dynamic range, integrate well with ASW608 Sub, and look great too. If you are looking for quality speakers to last 10+ years go with the 686 and avoid the M1's. I hope this helps some others thinking about the B&W smaller speakers.