I did a few more tests this morning. I wanted to check the 4K IQ, and I tried everything I could to induce moiré, but to no avail. I scrutinized the Red, Green, and Blue channels as well, and the results were impressive. I'm fairly certain it's due to the image processing because it blows away the already respectable 4K image from my Panasonic GX800.
And all of my tests were done with HyperSmooth on; it only gets better with it off.
I also tried my Konica 300mm f/4.5 on a tripod in 8K. I'm not sure there's much point in using 8K for distant landscapes, but for closer subjects, why not? I still think 4K looks just as good.
One thing this camera is not is a 1080p camera. IMO, they should let us use 10-bit in 1080p, but they don't. Also, when you switch to 1080p, it changes the color profile too. You have to go back and reset it when you resume shooting in 4K or 8K.
I think I'll just stay away from the 1080p modes unless I really need the 480fps and up.