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Is the TX-40CX680B too small to show-off its 4K panel? This highly talented and great value TV swerves that elephant in the room with some pin-sharp pictures to add to its impressive smart TV OS.
Making good use of its 4K panel, the TX-40CX680B offers excellent black levels, bold colours and mostly fluid motion sequences. It also manages upscaling from Blu-ray to 4K exceptionally well too.
The new Firefox OS impresses on both simplicity and customisation potential, while the upcoming arrival of Freeview Play won't hurt this TV's excellent value package.
The provision of only three HDMI inputs is a slight concern, as is its disappointing upscaling from standard definition TV channels and DVDs, both of which look exposed on this relatively small screen.
I also had a problem with USB sticks not being recognised, while the Firefox OS does lack a decent web browser.
Recording to a USB stick or HDD from the Freeview HD tuner appears to have dropped-off the spec sheet for 2015, too, which is also a shame.
The lack of 3D might put some people off, too.
Though the TX-40CX680B's 4K resolution is the headline-grabber, the emphasis from Panasonic on this 40-incher is on better pixels rather than more pixels.
Overall that rings true on the TX-40CX680B, though the standout exception is standard definition, which does look soft and noisy. Great colours and black levels help mark this TV out as something special, though if nothing else its 3840x2160 pixels offer proof that the 4K revolution is all-encompassing.
Will we even have non-4K TVs in a couple of years? Probably not.
Not solely because 4K proves irresistible, but because TVs like the TX-40CX680B are already the entry-level for other must-have features like smart TV, though few will get close to the new Firefox OS.
As impressively simple as the Firefox OS is, it's Freeview Play that will entice UK buyers. It was on the brink of availability at the time of this review, but judging by its canny integration into the TV's core user interface, it's raring to go.
From its low price-per-pixel to the latest in smart TV and catch-up apps, the TX-40CX680B could turn out to be one of the bargains of year.
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),