Willy - Yes - have the Panasonic about a week and a half or so. Have it in my main UHD system with a 65 inch Samsung 80T (just just about 7 feet away - pic below). Have mainly watched movies on it. Mainly Blu-Rays but have watched a couple of 4k movies as well as DVDs. Very impressed video wise with the player (had an Oppo 203 along with a 55 inch Sony UHD which I moved upstairs to the bonus room).
I've played a couple of cuts from audio CDs and also very impressed with the Panasonic as a CD player. I'm into file playback so that is something that wasn't tons of interest for me. It was just under double the price ($1k vs. $550) of the 203 but clearly to me is better. I've played with file playback a drop as well. Since it is not the main system, it probably won't see tons of use for high end audo. But it plays them very well. I have files on my Synology NAS in the office. I tried a variety of files at different sampling frequencies. Again very impressive. I think it is a bit smoother (with more options) vs. the Oppo 203. I have B&W P6s as mains (owned them since they were new in 1997) augmented by a Sumiko S.5 sub (Sumiko used to distribute Rel and it is a copy of a Rel T5, connected both for HT by the low level RCA connection and the high level Neutrik connected and set up using a one third octave RTA).
The room is 13x11 with a 10 foot ceiling. I have acoustical treatments including home made stuff and a couple of GIK acoustics art panels. When the house was built, I had in-ceiling surrounds put in which I am now using for Atmos speakers and I ran speaker wire along the sides for my B&W Leisure Monitor surrounds. I have a Marantz 5010 for HT and a Sherbourn Pre-1 (with HT Bypass) as a preamp and a Mivera SE amp to drive the front speakers.
The Panasonic has settings (if one wants) to sound like 6 different output tubes. They work via a button on the remote that toggles through them. I settled on number 3, which is described as a soft rich sound. These setting only work for sampling frequencies up to 192kHz. They also have 3 settings they call 'Remaster.' I haven't tried them. They are geared towards the genre of music and also work with sampling frequencies up to 192kHz. One is for 'pop and rock,' one is for 'jazz' and one is for 'classical' and they work by increasing the high frequency portion of the audio. I tried CD quality files, 24/96, 24/192, 24/88.2, 24/176.4, DSD and double DSD. It will supposed do up to quad DSD but I haven't tried any of those (I don't have tons of them). I have a few albums of 24/352 and they played in slow motion (the manual indicates it doesn't play them normally). There is, however, a 'Night Surround' mode (toggled by the same button on the remote) that dumbs files about 192 to either 192kHz or 176.4kHz. I haven't tried it as of yet.
When I first got the Panasonic, I searched the web for a bit to see if I could find evidence of an App to control the file playback. I have things in folders on the NAS (e.g. jazz non-hi-rez, rock and pop hi-rez, jazz and blues hi-rez, etc.) located in my office. The house was pre-wired (with my instructions on where to put things both low and high voltage and I ended up with 300 amp electrical service, including 50 amps for the main system) with Cat 6 and of course being a crazy audiophile (even though I may not use a system tons and donation are gladly excepted for my straight jacket - size extra large

) I have better than standard cheapo ethernet cables (for that system it is probably largely Blue Jeans Cat 6 since they aren't super expensive). I have lots of music files (I'm guessing a bit more than 50,000 and the discs are in a closet and if I buy new things I'll do downloaded files if possible as the closet is fairly full, including about 600 DVDs - the only discs I have out in AV furniture are the Blu-Rays - I probably only buy about a dozen music discs/year at this point). I couldn't find an App but I have downloaded 'DS Audio' which was made to work with my Synology NAS and I had it on my phone and iPads (I have a Hegel H190 Integrated/DAC/Streamer in another secondary system and I'm still playing with that at the Hegel doesn't do DSD, just up to 192, and has limited USB - for now using a small PC on its last legs using JRiver to dumb down sampling frequencies with a USB to SPDIF converter but have used DS Audio with the Hegel to play non-DSD) and yesterday was able to play the files with the iPad using the Synology DS Audio App (
https://www.youtube.com/watch?v=K-90MLAKd6g) and was happy with that. When I pull up the DS Audio App, it will give me a choice of players connected to the Network.
They are supposed to start broadcasting 4k in my area sometime this year and if so I'll probably end up with one of these shortly thereafter -
https://zapperbox.com/ I just do over-the-air and get Netflex and Amazon Prime over the high speed internet. The Samsung comes with a ton (besides all the usual video streaming Apps) of internet TV channels they call Samsung TV. I haven't thoroughly explored them (not a huge TV person) but at some point I'll take a closer look.
