So i bought my parents a Panasonic Viera TX-48CX400 4K Smart TV but i found out about HDR later after i got it. Is HDR really worth it though? i paid only 499,99 euro for this TV, it was on sale and sold out a day after. Few Youtube video's at 4K stutter but most are smooth, not sure if TV is at fault. Has a pretty old OS on it as well and not as fast as i hoped for. Picture quality is great though, blacks are deep and colors pop but have yet to calibrate it. One thing i noticed is the backlight in the corners can be seen noticeable but not extreme. There aren't many options for a little more money, i'd have to pay like 150-200 euro extra if i want a more decent 4K TV.
Yeah I wouldn't worry about it. And the Youtube stuttering is probably caused by the crappy WiFi most cheap TVs have.
So far, I've yet to use a TV with a snappy OS. My newish 4K TV (LG) and my last couple 1080p sets have had excruciatingly slow or cumbersome menus. I usually spend in the $400-800 range though. Perhaps really expensive sets are snappier. I use a connected Roku and PC for the most part though. The built in stuff is cool for once this 4K set gets orphaned down the road.
Maybe not for your model but Panasonic are releasing a HDR update soonish. The stuttering may be down to the processor, i have brand new TX50" and a TX55" Pannys and they are smooth as silk.
We're selling the TV next month, we can't exchange it anymore. I'll be spending around 300 euro more then this one, one that has at least everything and more smart hub options. Our old Samsung TV has more options then this one but i guess thats what you get for a low budget 4K TV. Don't get me wrong, the picture looks epic when i watch a 4K Youtube scenery video. About the stuttering of 4K videos, i think it depends how they are uploaded? some are smooth without issues and some stutter so bad the audio cuts out.
I bought a Samsung 55KU6300 recently for $550. The OS is snappy which I was surprised by for what is considered Samsung's low end smart TV line. It supports HDR but the panel is only 8-bit, so there is little to no difference when it is turned on. My only complaint so far is the lack of a Spotify app. Apparently Samsung revamped their TV OS last year and Spotify has yet to release an app for it despite it having been on their previous models. For the price I really can't complain. As a bonus the input lag is just 20ms when game mode is turned on, half what my previous Toshiba was. So it is a great TV for gamers. EDIT - Spotify has added an app. The interface is not great, but I just use my phone instead of the remote to control it and it is fine.