Ryzen 5000 series is energy-efficient enough to be a perfectly viable option these days, even compared to Intel 12th gen. I would choose Ryzen 5000 if I was building a new high-end
Blue Iris box today.
Quick Sync should be worth more than a 5% reduction in CPU usage. In the past I have measured
close to 50% savings from Quick Sync, but more recent tests (tonight), the savings are closer to 25%. I don't know if it is because of any change in Blue Iris or if it is all due to my configuration and set of cameras, all of which is rather different than it was 3 years ago.
That said, Quick Sync has always had some issues in Blue Iris. I think it adds a tiny bit of video delay (I think I feel it, but I don't have a great way to measure). It causes graphical corruption sometimes with some cameras. It has caused memory leaks with a wide range of Intel GPU driver versions. Sometimes you get black frames when starting clip playback. Sometimes hardware acceleration just turns off for individual cameras for no good reason, so you cannot rely on it staying enabled. I cannot fault anyone for just using software decoding if they've had problems with Quick Sync.