How would this model stack up against the 875 in terms of features/power?
Power, it should walk all over the 875. The NR1000 has a much larger power supply and it is a toroidal. The flexibility is killer, and it is completely modular. This was the receiver that was advertised as "the receiver Nostrodumas would buy." The video processing would be better as well as a few other things on the TX-SR875, but those are only video related things. You can still get 7.1 high res audio on the TX-NR1000. It cah have two 7.1 systems connected at once, but can't be run simultaneously, but still pretty neato!
Sorry for continued editing for anyone that has already read this post...
This receiver includes a notch filter, which can help get rid of bass humps.
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Five channels driven continuously into 8-ohm loads:
0.1% distortion at 163.5 watts
1% distortion at 187.9 watts
All channels driven continuously into 8-ohm loads:
0.1% distortion at 125.3 watts
1% distortion at 167.8 watts
http://www.hometheatermag.com/receivers/106onkyo/