Dapack,
You said the TX-NR906 doesn't use the triple inverted darlington output stage. That's peculiar considering it's supposed to be a higher model than the TX-NR1007. I remember when the TX-SR805 came out it was the most robust amp section I'd ever seen in a receiver that price. The TX-SR875 used the same output stage, and the TX-NR905 used a toroidal transformer, and what appeared to be the same output stage.
Then came along the TX-SR806, a leap backward from the TX-SR805 in so many ways, yet the TX-SR876 seemed to hold the same values as the TX-SR875. So what did the TX-NR906 do differently that time around, or was the TX-NR905 the same in the amp section as the TX-NR906 and both where somehow inferior to the TX-SR805, TX-SR875, and now the TX-NR1007?