I got my 820 setup last night and ran through some material to get a feel for how it performs. First, off I am using an older JVC 4910 that is not HDR. I am sending it 4k SDR BT2020 with the BT2020 color profile installed on the projector with an HDFury Integral to handle the EDID and HDCP handshake. So while I can't use the HDR optimizer than lets you pick a display type with the appropriate light output, I am using the optimizer parts that let you tweak the dynamic range. Interestingly the old "slider" called "Luminance Adjustment" is still there but is now for SDR content. The new dynamic range adjustments are under the optimizer options during playback. The main control that functions the same was as the ub900 slider is called "Dynamic Range Adjustment." There is a brightness control as well and bright and dark tone curve controls
So while I can't speak to the new HDR tone mapping for specific display types, I can say that from what I saw last night, SDR tone mapping is at least as good as the ub900. Also interesting in my case is that both the ub900 and the 203 would sometimes have a thin 1 pixel line down the right edge of the image that I would get rid of with the masking controls on my projector. It happened with some titles and not others and only when sending bt2020, but not rec709. I ran through about 10 discs including ones I know always resulted in that line, but it did not occur once with the 820.
The player itself is nicely build, comparable to the ub900. I didn't notice any objectionable drive or fan noise as some had mentioned. It is a lot faster to load and respond than both the ub900 and the oppo 203. I did find a strange audio delay when outputting PCM vs bitstream. I noticed during the 20th century fox logo, the second one that you hear when the movie is actually started. There is noticeable delay between the front and rears. Bitstream is fine. If this can be replicated I am sure it can be fixed.
My only real gripe is the remote is no longer the nice backlit version from the ub900 and now is the standard Panasonic remote. Now I'll be using my harmony anyways but it drove me nuts last night hitting the wrong buttons in the dark when tweaking settings. Especially hitting the Netflix button!! So I ordered a ub900 remote off ebay. Not necessary, but it'll save me frustration when I want to adjust the dynamic range settings on the fly.
I think Panasonic accomplished what they set out to do with the ub820. It's a solid, fast player. And once it gets the dolby vision update, it will be the most complete player on the market as far as HDR options go. So far so good.