Just as a counter balance I own three Onkyos a 606, a 707, and a 906 and they are all working great. The 906 is on 18 hours a day 7 days a week. The 606 and the 707 were bought factory re-certified.
I like the 906 wish I could have found a great deal on it like I did my 1900.
Big amps I bet you are happy with it. After my 805 had HDMI heat related issues I got smart and installed a 6" fan blowing my AVR now. Opened up the back of the cabinet and 6" venting space above the AVR. I never stacked on my 805...oh well any brand will have a problem. Great AVR you have,
best of luck with it.I am retired and my AVR and flatt screen are on all day too

Kids are grown now, my turn to play all day.
EDIT Looks like you use it as a Pre/Pro nice gear you have.