The 55LW650T's 3D performance is nothing if not eminently watchable and offers a few immediate advantage over active technology.
The passive system means that you simply pop on the lightweight glasses and the picture snaps straight into 3D without any delay while everything synchronises. It's refreshing not to have any flickering in your peripheral vision from ambient light and – initially, at least – there is no hint of eye-fatigue.
The 55LW650T's 3D pictures also look brighter and less prone to crosstalk than those of most active 3D TVs.
Possibly the single greatest thing about the 55LW650T's 3D experience, though, is that it can be shared with so many other people. Sharing active 3D usually involves having to pass a couple of pairs of glasses around while everyone else stares in anticipation at a blurry picture, but up to seven people can join in the 3D fun with any 55LW650T and extra glasses cost just £2.
Given the potentially social nature of 3D, where it will likely be used for group or family viewing sessions of events like sports or films, the affordability of the passive option is enormously persuasive.
On the other hand, LG's repeated claims that its passive technology can compete with active for raw picture quality don't quite stack up. Particularly evident, at least on a screen this large, is a reduction in resolution when watching 3D on Blu-ray and on some broadcasts. This is particularly evident during motion and over backgrounds, such as trees or textured walls.
It could be that LG's only fair-to-middling motion processing doesn't help when it comes to 3D clarity, as the processing causes some artefacting when it's on, but leaves the picture looking a touch blurry when it's off.
To be fair, though, as noted in the review of the 47LW550T, the picture doesn't appear to be merely standard-definition, as you might expect, but is somewhere between standard and true hi-def. If you want to marry 3D with the full resolution of your HD TV, though, the passive route might not be for you.
A further passive-specific issue is that we could make out narrow black horizontal lines in the picture in 3D mode caused by the filter on the screen. These also produce a little jaggedness and 'striping' over the edges of contoured objects in 3D mode, with the former in particular becoming quite pronounced over very shallow curves. The passive film on the screen also causes minor striping and jaggedness over the edges of objects during 2D viewing.
It should be stressed, however, that these issues reduce the further you sit away from the screen. With this in mind, it might be that passive technology is better suited to smaller screen sizes than this 55-inch monster.
Another limitation of the 55LW650T's passive 3D pictures is their viewing angle. Move far down the TV's sides and you can start to see a slight wavy-line effect presumably caused by the film on the screen, while having a viewing angle of only around 10° or greater above or below the screen greatly increases the appearance of crosstalk.
Speaking of which, the 55LW650T's 3D pictures aren't as totally free of the stuff as anticipated. There are clear moments of double imaging, even with scenes that don't show this problem on plasma TVs. It's more subtle than it is with most active 3D screens, though, and appears more as a gentle shimmer or local loss of focus than the very clear double ghosting witnessed on active 3D displays.
The last point concerns the 55LW650T's 2D to 3D conversion, which delivers not much more than a fairly shallow effect that exhibits noticeably more depth errors than the best rival engines.
In the final analysis, the 55LW650T's 3D performance is in many ways exactly what you might expect. Quality might not be as high as you'd find on one of the better active shutter sets, but it is far from unwatchable and is arguably more relaxing if you're affected by flickering.
First impressions of the 55LW650T's 2D performance, meanwhile, are very good. Pictures from a combination of HD broadcasts and Blu-rays are punchy, thanks to a winning combination of an expansive contrast range with vibrant, well saturated colours. Predominantly dark scenes benefit from a very profound black level response, but the picture can also go bright when required, with the screen having the requisite power to overcome the darkening effect of the 3D film filter without difficulty.
Also impressive is the sharpness and detail with HD sources, which fully reveal the impact HD can have on a screen this large. Occasionally the sharpness goes too far, tipping the picture over into looking rather noisy. And there's a touch of moiré patterning over patches of very fine detail, but for the most part, if your source is excellent, then so, it initially appears, are this TV's HD pictures.
Unfortunately, though, the more you watch the 55LW650T, the more it becomes clear that the occasional appearance of grain is not the set's only significant issue. Another is that motion doesn't look wholly convincing, with either marginal resolution loss without TruMotion, or slight edge artefacts with the processing engaged.
The biggest problem by far, though, concerns that old edge LED chestnut, backlight inconsistency. While black levels in uniformly dark pictures are reasonably consistent with the local dimming mode switched on, you can see distractingly obvious 'blocks' of light around any bright elements that appear in the picture.
Yet if you turn the local dimming off, the panel suddenly exhibits obvious signs of backlight inconsistency, with large patches of the picture looking much brighter than others. Even with the backlight toned down to just 30 per cent it looks like someone's shining a low-powered torch onto each of the picture's four corners.
With standard-definition broadcasts and DVDs, the 55LW650T proves an able rather than spectacular upscaler, repressing video noise quite well, but not making pictures look particularly sharp.
Finally, there's the 55LW650T's rather disappointing gaming performance. While pictures remain surprisingly and gratifyingly short of the sort of motion blur and trailing sometimes seen when playing games on LCD TVs, the set's measured input lag, even using its dedicated Game picture preset, is a depressingly high 101ms. You can expect this to result in a considerably diminished performance with pixel-precise platform games, and twitch-trigger games like Call of Duty.