I recently spent quite a bit of time listening to some B&W DM12's and DM16's amplified with a NAD 2100 PE and a Quad 405. I compared this with my own more modern Jamo C603's. These old B&W speakers still sound fantastic when good supplied with high quality music. They are very revealing and will show out a bad recording very quickly but they are also quite musical.
I preferred the DM16's (which are also a lot bigger) to the DM12's. They have a fuller sound and broader range. They sound quite musical and in many ways similar to the Jamo C603's. As for the amplification both amps are excellent and have an abundance of power and easily gets the speakers to listenable volume. I prefer the NAD to the Quad, but I didn't have to much time to compare them. The NAD has tighter en more solid bass and I couldn't really tell the midrange and treble apart. The Quad is known for struggling with lower impedance speakers, but does perform excellent with speakers with an impedance of 8 ohm or higher.
I really appreciate the older amplifiers and loudspeakers and they are still top contenders against many of today's modern speakers.