Pictorially, as you'd expect given that it uses the same picture technology, the 42PX700 is just as impressive as the 42PX70.
The most immediate impact comes from the outstanding depth of the picture's black levels. The night-time backdrop to the scene where the Mission: Impossible crew steal the ‘rabbit's foot' in Shanghai is pretty much flawless. Which is to say it really looks black rather than washed out grey as happens on many flat panel TVs, and yet there's also clear evidence of shadow detailing in even the darkest corners of the city, lending the scene a truly cinematic sense of scale.
Great black level performances like this are generally accompanied by rich, natural colours, and that's emphatically the case with the 42PX700. The vibrant tones of the Florida bridge assault sequence are perfectly saturated, bright and free of noise, while subtler fare such as the skin tones during the interiors of the Mission: Impossible HQ looks effortlessly believable.
The TV also does a good job of reproducing the superb levels of HD detailing in the Mission: Impossible III Blu-ray disc. And as ever with a plasma TV it's a real treat to see fast-moving sequences like Cruise's sprint down a river-side alley in a Chinese fishing village delivered with precious little of the sort of motion blur that afflicts most LCD-type TVs. Crucially the 42PX700 also avoids that common plasma motion problem of dotty noise over moving skin tones.
With practically no sign of plasma's traditional problems with showing smooth colour blends either, the 42PX700 really does deliver a showstopping home cinema experience. But that's not to say its pictures are completely perfect. We've seen slightly sharper HD images and even brighter, more dazzling colours from one or two of the best LCD rivals, for instance. Plus horizontal motion sometimes judders a touch, and some sharply contrasting edges look slightly jagged from time to time. But so good is everything else about the 42PX700's pictures that these flaws are easy to live with.
There's no doubt that the 42PX700's extra audio power makes its presence felt, and its extra HDMI is a boon. Yet strangely that doesn't mean we automatically say you must buy one. It is recommended, but the 42PX700 also tends to sell for a slightly hefty £250 more than its 42PX70 sibling, so unless you're really desperate for the more expensive model's extra audio power - as in, you have a big room to fill and don't want to get a separate audio system - then we'd actually suggest you stick with the 42PX70 and put the money you save towards getting yourself a nice new HD source.