"Since it is not a mature technology yet, price/performance curves *do* suggest that class D will be challenging the current art. But not today."
The Nuforce Ref 9 is the best amp i owned, and i owned a few from Pass, GamuT, Krell, Conrad Johnson, Tact etc...
I know one guy who sold his 25.000$ pair KR Audio Kronzillas for a pair of Reference 9.
You cannot say that it's not mature.