The KD-55X9005A represents a huge step forward in TVs, but it's not quite as perfect as it thinks it is. Let's start with the headline act - detail.

Sony claims that, such is the tiny size of the pixels, it's possible to sit much closer to this TV than to a regular Full HD model. Around 1.5 times the height of the TV, in fact, and though we'd broadly go along with that (the pixels are so small they're almost impossible to see), that only applies to 2D. Watch in 3D and you're better off sitting further back, where you usually sit. Two rows of sofas, anyone?

sony KD-55X9005A

Back to the detail. Native 4K footage is awesome. In our reservoir of 4K samples were trailers for After Earth and Total Recall, the latter of which we also had on Sony's 'Mastered in 4K' Blu-ray disc (so in Full HD resolution).

Despite 4K X-Reality PRO, the two don't compare; the subtlety of the light and the pin-sharpness of close-ups in the native 4K version are quite brilliant.

The Blu-ray version is actually almost as good, however, and 4K X-Reality PRO is clearly doing its job; watching Blu-rays (and not just 'Mastered in 4K' versions - we watched Hugo and The Amazing Spider-Man, too) on the KD-55X9005A is a real treat.

Reality Creation is a key technology here, effectively dressing up Blu-rays as something akin to 4K, complete with sharp edges and saturated blocks of colour. It's clever stuff, though occasionally the upscaling is overdone, and close-ups can look a little thin. It's worth underlining how brilliant the colour is on everything the KD-55X9005A displays.

However, 4K X-Reality PRO can't do much about this TV's endemic structural issues, which are slight but noticeable.

sony KD-55X9005A

The most annoying is motion blur; even with Motionflow XR 800Hz on its 'Clear' setting, each time the camera pans that awesome 4K image blurs, retreating into something visibly less than Full HD. It's very noticeable on the many FIFA Confederations Cup football 4K clips provided to us by Sony; camera pans blur, and the ball leaves a trail and a double image. Ditto in some tennis clips. What a shame.

There's also a worry over this panel's native contrast. With the lights off there's a bluish look to dark scenes, denoting some LED clusters, though LED Dynamic Control addresses this pretty well. Black levels are acceptable but, again, not as impressive as on Sony's high-end Full HD tellies - solid blocks of black contain little in the way of shadow detail.

Nor is 4K X-Reality PRO the cure for all ills it claims to be. It makes a decent stab at upscaling Freeview HD channels, but regular standard definition fare isn't as comfortable to watch as on a decent Full HD TV. The same goes for DVD, whose ragged edges are delivered with visible blocking, though the KD-55X9005A does handle digital files well.

Some hi-def MKV trailers we had looked fabulous, though for some reason some AVC HD files from a camcorder appeared over-upscaled.

sony KD-55X9005A

We've been listening to analysts say that Passive 3D - thus far hamstrung by a lack of pixels on Full HD sets - won't come of age until Ultra HD hits the stage. Well, that's now - and we're here to report that Passive 3D on the KD-55X9005A looks fabulous.

The horizontal lines are still visible (particularly in long-shots, but never in close-ups), but only if you look for them. Sitting further back helps, too, but overall the cleanness, sharpness and completely crosstalk-free 3D images are a delight. Our only regret is that there were no native 4K 3D samples for us to test with.

We are, however, conscious of one 3D fact; in terms of detail, 4K active shutter 3DTVs look even better.