Not surprisingly given its Full HD nature, the P42S10 really springs to life with high definition. Colours, curiously, look more authentic and even slightly more vibrant; the effects of the 400Hz system become more pronounced, especially when watching Blu-ray; and you also become more aware generally of how this screen's plasma nature all but does away with the response-time blurring seen with many LCD TVs.
It's also worth stressing that the effectiveness of the screen's black level response becomes even more important when you're dealing with the extreme contrasts found with a typical film as opposed to a 'flatter' TV programme.
Even with HD footage, though, the image didn't seem somehow quite as sharp and detailed as I'd expected. Also, although the 400Hz system on the P42S10 makes motion and horizontal camera pans look smoother - without causing serious processing artefacts - than they do on Panasonic's X10 plasmas and any previous Panasonic plasma screen generations, judder certainly hasn't been completely removed by any means. There certainly seems markedly more of it than you get with the 600Hz G10 range.
The P42S10's sound continues the generally winning formula found on most of Panasonic's recent flat TV output. Volume levels can get strikingly loud without distortion setting in, the mid-range is open enough to ensure that dialogue is still audible during action scenes, and there's much more bass around than you commonly get with a flat TV. The only problems are that this bass can occasionally leave some male voices sounding a bit soupy, and some treble details a little pushed out of the mix.
If you're in the market for an affordable 42in Full HD home cinema screen for a dedicated - i.e. very low lit - viewing room, the P42S10 is definitely worth considering. But while it delivers a typical Panasonic black level master class, and certainly has its moments, it's not quite successful enough in all areas of its picture performance to unreservedly recommend as a main living room TV. In short, if you can afford to step up to Panasonic's superior G10 range (a 42in model of which will set you back another £150 or so), I'd recommend that you do so.