The Denon AVR-1906 doesn't have any HDMI audio or video processing, it's no comparable to the Onkyo. The Onkyo also has really good power benchtest results (it just falls under it's ACD rating (not common with most manufacturers). The Onkyo's overall features, power, and connectivity are not comparable to the Denon.
The Onkyo does tend to run a tad warmer than the competition, but I would just put a fan on it and call it a day if you have to.