With its Ultra High Definition native resolution, groundbreaking 'Full HD' passive 3D system, hi-fi level speaker system and specially developed, ultra-powerful video processing, Sony's KD-84X9005 is an incredibly ambitious bid for TV greatness. And yes, it's got a £25k/US$25k price tag that wholly reflects the extent of its ambition.

But it really is glorious. With native 4K material it produces far and away the best picture quality we've seen on a commercially released TV, with levels of detail, colour accuracy, clarity and depth that shift your experience from just watching TV to actually feeling like you're looking through an open window.

Its 3D images are a revelation too, as the 4K resolution combines with passive 3D technology to jaw-dropping effect.

The set's operating system could be better, and the backlight isn't entirely perfect. But neither of these flaws do much to stop us confidently proclaiming the Sony KD-84X9005 the best all-round TV in the world right now. All we need now is more 4K/Ultra High Definition sources to exploit it with.

We liked

Native Ultra HD pictures look unbelievably good, and the set's upscaling of HD images is enormously impressive, too. What's more, the passive 3D pictures are a joy to behold, injecting new life into the ailing 3D concept, and the set's audio is extraordinarily potent for a non-separates system.

We disliked

However much the TV might ultimately justify it, you can't exactly ignore its £25k/US$25k price tag. The operating system looks low-res and is a faff to navigate too, and the speakers only work at their best if you sit in a quite small sweet spot.

Finally, our test sample suffered some backlight consistency problems - but other samples we've seen in demos haven't suffered nearly as much with this, making us suspect that our test sample could be slightly faulty in this area.

Final verdict

Its backlight isn't as clever as that of Sony's HX853 TVs, and its operating system could be better. Plus it's truly, intimidatingly expensive. However, with native 4K content - if you can find any - the Sony KD-84X9005 is the best TV ever made. Period. No argument.

With 3D, the Sony KD-84X9005 is the best TV ever made. And thanks to the quality of its upscaling, we'd even say that after a little tweaking of its processing settings it's the best TV for watching current HD sources on, too. Job done, then.

Also consider

Given the uniqueness of the Sony KD-84X9005's proposition, there's nothing very direct for us to include here.

Thinking out of the box a bit, though, there's Sony's VW1000ES projector. With its true digital cinema native resolution of 4096 x 2180, this enables you to enjoy the joys of 4K/Ultra High Definition on an even greater scale than the Sony KD-84X9005, while costing less in the UK or the same in the US.

However, projectors aren't as convenient to install in a normal home environment as a large TV. The Sony KD-84X9005 also produces pictures of considerably greater brightness.

The only other 4K TV you could consider is the Toshiba 55ZL2. This does indeed look spectacular with native 4K sources, and also delivers glasses-free 3D.

However, it's much smaller than the Sony KD-84X9005 at just 55-inches; the glasses-free 3D is flawed to say the least; and worst of all, the 55ZL2 is incapable of receiving 4K video inputs.