In some ways the 50PK790's pictures represent a considerable leap forward from last year's LG plasmas, and with HD at least are capable of looking really quite excellent.
The best of the good news finds the 50PK790's black level response going much deeper than the slightly milky look of last year's screens, at least once the TV has been calibrated correctly.
Dark scenes can look convincing, detailed and, well, dark.
If the word 'calibrated' had you groaning with fear back there, don't worry; the black level improvement has allowed THX to deliver a much superior THX Cinema setting than anything provided on last year's LG plasmas. So just choose that when watching HD films if you want an easy life.
Actually, the much-improved black levels aren't the only things that help the 50PK790 produce a better THX preset. For LG has also come on leaps and bounds with its colour response for this new plasma TV.
Colours look richer with a greater dynamic range, yet they also look more natural thanks to a marked reduction in the extent to which greens dominate dark scenes and oranges dominate reds and skin tones.
There's more subtlety to be seen, too, in the way the 50PK790 renders fine blends, with practically no ugly colour striping around, and no blotching to skin tones during HD viewing.
As we find with many plasma TVs, colour accuracy diminishes when you switch to standard definition material, but again this doesn't happen nearly as severely as it did on last year's LG plasmas.
More good news finds the 50PK790 avoiding the motion blur so common with rival LCD technology, but also handling judder well thanks to its '600Hz' system.
Even with LG's anti-judder Film Mode in play, you don't get the total, almost freakish fluidity that you can obtain from Panasonic's top-stream plasmas, or Philips' high-spec LCDs. But the minor amount of judder the 50PK790 leaves behind actually feels quite natural to our eyes - especially as the Film Mode processing doesn't appear to generate anything particularly significant in terms of unwanted side effects.
The 50PK790 excels, too, at reproducing the clarity and sharpness of good quality HD feeds. In fact, it's so forensic in its approach that it easily delivers the natural film grain when showing Blu-ray movies that's so beloved of serious cinephiles.
Not that the 50PK790 is only an HD tool, though. Aside from the occasional colour tone issues noted earlier, it actually upscales standard definition pictures reasonably well provided they're of a passable quality in the first place.
While the 50PK790's pictures are capable of looking quite outstanding at their best, though, there are two main picture problems. The first finds that while black levels are a big step forward compared with last year's LG models, they're still less profound than those of some new Panasonic plasma models.
The most alarming issue, though, finds the 50PK790 still suffering with the same image retention problem noted on last year's LG models. At its lowest level, this can find really bright image elements in dark scenes leaving momentary but clearly visible shadows behind.
At its highest level, if you leave something bright and, especially, colourful - like a channel logo - in the same place on screen for as little as an hour, you will be able to see a shadowy relic of that logo apparent over even quite bright pictures for a considerable time after you have changed channel.
For instance, after watching Sky News for a couple of hours, we decided to fire up the excellent Borderlands on our Xbox 360, and were alarmed to see a clearly readable relic of the Sky News logo appearing in the blue skies above Pandora.
And while watching Casino Royale on Blu-ray, we were perturbed to suddenly see the letters S and T appearing in a patch of blue sky behind Bond as he hung off the back of a van during the film's 'Free running' sequence.
We couldn't even remember what we'd been watching that might have caused these residual letters, but the fact remains that they were there, and they were clearly and distractingly visible.
We should say that we didn't experience any permanent 'screen burn' during our tests, and we would expect the issue to diminish after the first 100 hours or so of use. But the problem was certainly enough to cause irritation on a few occasions - especially as other plasma manufacturers seem to have almost completely eliminated this old problem now.