haha probably the Denon route. I like TLS guy's advice to avoid vietnamese and china brands. so likely the 4800.
I think you are correct. Unreliability and premature failure is a massive PITA. Assessing reliability in any purchase is the toughest part, and impossible to be precise about. However others experiences matter.
One nutter here thinks I had a hand in the failures of the 7705 and 7706 when I absolutely did not. They were in an absolutely optimal environment. Now it is not that you could never have a failure and even an early one. How the manufacturer handles failures is very important.
I have been lucky, and had very few equipment failures in 70 odd years. This is partly equipment selection, but I take care of it and don't abuse it. All my serious issues have involved my AVPs.
This has been the story. My first AVP was a Marantz 8003 in 2006. It failed almost right away due to a regulator in the power supply failure. The then owners of Marantz had it fixed and returned at what I would call lightening speed.
In 2012 we had a Townhome here in Eagan, that my wife mainly used while working at Allina Heart Institute. I have to admit the system there was rather cobbled together. She demanded an upgraded system. So I bought my first 7701 and installed a 3.1 system with a Panny plasma TV. Both are still working.
I liked it and bought another to replace the 8003 at our lake home and bought a larger Panny plasma TV. Both are still in regular use, in our great room and family room. The 8003 is in storage and as far as I know still works.
So when we moved from the lake home we built our current AV room which was 11.2 because I had the gear to it except for the AVP. That is when I bought the 7705 in 2019.
It developed a hum present even when muted and eventually sent out a gigantic bang and took out the output to the left rear surround. Fortunately no speakers were damaged. Marantz under Masimo/Sound United did not have the parts to repair it, which in itself was a disgrace.
So, unwisely I bought a Marantz 7706, this developed a similar fault in 3 months. So I took it out of service and bought the AV 10, which I should have done right after the 7705 debacle.
Now the 7706 has been in for repair for almost five months. All I have heard is that they have sent it, to a different facility. Which ever way you look at it, that is dreadful customer service. Both the 7705 and 7706 were made in Vietnam. So clearly both have had a component failure and by the way they behaved, most likely a cap failure.
Now, I believe all this is relevant to your question in the first post.
Harmon have only had Sound United for a few short weeks, and have had nowhere near enough time to bring about meaningful change. The worst thing that can happen with a major purchase is early failure, especially if customer support is lousy to non existent.
So, I have been trying to steer you to reliability. I think Yamaha is probably a safe choice as I stated.
For Denon at this time I have to say that a unit manufactured at the Shirakawa plant in Japan is the safer choice. The above are my reasons for giving you that recommendation.