I had constant issues with my last Yamaha 6150. hdmi board. Sent it in for repairs, warranty but had to pay for shipping, still wasn't fixed. The Yammie before that,similar issue with hdmi but in fairness it was one of the first with hdmi - rxv-4600. That is now powering my atmos speakers. Very strong amp, runs 4 ohms all day long.
Denon x4000. Used 16 hrs per day. 2 years now. Red lights and shutdowns after 11 months. Redone all cables, still did it. Factory reset it a few times...seems ok. But I still get some popping in speakers when it turns on.
Denon x4100. So far so good. But only used on weekends and 1 year old.
Denon Multeq is far better then ypao. But ypao is good, you just need to learn how to use it. Denon's multeq is very easy, and their onscreen menus easy, and their ability to send hdmi to other zones without rca's is great.
Both good names. Both sound good, different, but good. Yamaha is a bit brighter and better for music. Denon better for movies.