I am not saying don't buy an Onkyo, they are good avr's, just realize there may be some issues down the road and possibly sooner than you may like. When working they are very good.
I own a Denon 3808 and have grown disenchanted with Denon's latest models, they appear to lack the quality my 3808 has. They appear to have smaller power supplies, capacitors etc. I suspect the parent company has toned down the Denon line in favor of pushing Marantz as the upper end, just my opinion on this idea. I have no proof of this practice other than the Marantz line appears to be maintaining or even improving their quality over the years which I found equivalent to older Denon's like mine.
Pioneer and Yamaha appear to have brought up their level of quality over the last few years and appear to be good choices right now.
My current favorite avr is from Anthem the MRX series.
I would tend to agree with your overall assessment. I have owned a couple of Yamahas the last go round and currently have the CX-A5000 Pre-pro which is excellent and they just provided a firmware update for HDMI 2.0. From a pricing perspective, when comparing similar model categories to Pioneer, Onkyo or Denon, the Yamaha product is a somewhat better value and the "Aventage" series has a four year warranty where the others have a maximum of three. For me, the Anthem AVRs, although I am sure excellent sounding, are a little short on features. Although I expect nothing to change in the near future, with the purchase of Pioneer by the group that owns Onkyo, who knows down the road what will happen there?