What is the secret of their good sound?
I don't know any secret. They match all components in pairs, used per each channel (i.e. manually, post materials purchasing phase) -- but that's not a secret. That may be a contributing factor.
Are the technical people at FM Acoustics and Boulder smarter than the people at Madrigal or Krell
:) Unlikely, I would say (Ok, I realise you're joking). Just a different product category aimed at a different market segment...
ASAIK, FM sells mostly to the pro market anyway.