I saw this thread a while ago and found it interesting but I was waiting for delivery of the Watt/Puppys and wanted to see if my listening experience would provide any insight. I have been listening for about three weeks so here goes.
I am not sure what Martin Collums is hearing that is different from what I hear, if anything. I have noticed listening to rock, folk, Celtic, jazz and live recordings is that the Watt/Puppys are so spectacular on the less crowded music, such as acoustic guitar or piano with a vocalist, that it may make them seem less spectacular on other music. The individual instruments and vocalists seem to hang in space and are almost three dimensional. It's as if you can hear not only the sound being created but the shape of the instrument creating it. It can be spooky.
On more densely packed music, the detail, tonal balance, imaging, sustain and decay are all still present for each instrument and vocalist but you have to pay more attention to pull them out and the Watt/Puppys kind of seduce you into listening for those individual details. They have plenty of dynamics, drive punch, whatever you want to call it, to convey the emotion of the music. I would not have chosen "reticent" to describe the sound.
@inthesticks you will love yours when they arrive. They are worth the wait.