Importance in this order, Most important, to less important
Warranty, and Customer support
Support of most all current formats, audio streams, video specs.
Must have at least 7.1 pre-outs, as well as toslink optical input (assignable).
Must have HDMI, at least 4 inputs.
Integrated Amp not necessary, although I prefer to not have amps integrated, read on...
Long story short, I've had 2 Onkyo, 805, and 806. Both eventually having issues with different amp channels. Sometimes working ,sometimes not working.
My 806 currently pops for the first 1 minute, sometimes QUITE loud, and I fear for my speakers. All the caps look great, and there is no evidence of any of the power transistors being blown.
I currently have a pretty old Carver amp, 250wpc which I will use first if I end up getting a pre/pro, and then work on getting amps for the other channels.