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It's really hard to argue against the 40DX600 in terms of value. Some might bleat that including 4K resolution at such a small screen is pushing it, but the good news is that those extra pixels don't negatively affect the image quality on lower quality sources.
The choice of desktop stand array might attract some, though any feeling of premium quality won't last for long – the 40DX600's build is fairly lightweight and lacks the solidity of TVs further up the food chain.
However, if you want small-screen 4K for as little spend as possible, this 40DX600 is the sweet-spot.
By supporting 4K from YouTube, Amazon and Netflix – as well as every downloaded 4K file we could find – the 40DX600 shows itself as truly 4K in every sense. Better still, images are clean and retain detail.
Key here is the 40DX600's excellent motion resolution, which keeps 4K looking sharp – though its small size means that bright and colourful footage – such as sport – is much more impressive in 4K than movies are. Black levels are convincing, and somewhat surprising is the 40DX600's lack of light spillage in the corners. There's clearly a very capable VA panel inside.
However, it's the spotless and speedy Firefox OS that takes most of the credit for making the 40DX600 a fine living room TV that's fit for the 4K future.
Aside from the lack of wow factor from 4K movies – something we can blame on the 40DX600's small size (50-inch is where 4K really starts to impress) – this 40-incher has few cons. Perhaps the main drawback is the tight viewing angle, which means colours and contrast draining if you watch from anywhere away from head-on.
Some may also mourn the lack of 3D, which had become a standard-issue feature, but now appears to have been completely cut. For those with even a couple of favourite 3D Blu-ray discs, it makes buying a new TV a slightly more painful process than it could be.
If you want 4K at the cheapest possible price, the 40DX600 is Panasonic's sweet-spot, but its talents stretch further than simple pixels. Excelling with bright 4K footage and all kinds of Full HD, this 40-incher nevertheless fails to make 4K movies truly pop.
There's a slight issue with viewing angles, but otherwise the 40DX600 handles all sources with consistent clarity, with plenty of colour and motion sequences that are smooth enough, though images never reach benchmark quality.
However, this TV's likability is largely down to the presence of the immaculate Firefox OS and a great choice of apps. It may stand firmly in the mid-range of Panasonic's latest crop of 4K LED TVs, but the 40-inch 40DX600's app-packed Firefox and its clean and colourful images make this a great value contender.
Jamie is a freelance tech, travel and space journalist based in the UK. He’s been writing regularly for Techradar since it was launched in 2008 and also writes regularly for Forbes, The Telegraph, the South China Morning Post, Sky & Telescope and the Sky At Night magazine as well as other Future titles T3, Digital Camera World, All About Space and Space.com. He also edits two of his own websites, TravGear.com and WhenIsTheNextEclipse.com that reflect his obsession with travel gear and solar eclipse travel. He is the author of A Stargazing Program For Beginners (Springer, 2015),