Unfortunately the DMP-B15's disc loading times leave a lot to be desired. With our usual test disc, the Java-heavy Spider-Man 3, it took 59 seconds to get to the Sony Pictures logo after shutting the disc tray, which is a long time to wait in anyone's book.
But when it finally gets there, the picture quality on offer is tremendous - clean, vibrant and emphatically hi-def. We were a little concerned that the WSVGA screen might not communicate the 'hi-def difference' as convincingly as a 1080p screen would have, but with Children of Men in the tray our fears were allayed from the start.
This disc is bursting with detail in every scene - discreet background minutiae that helps convey a believable vision of the future - and the DMP-B15 lets none of it slip through the net. The filth-ridden London streets look horribly lucid, and Clive Owen's stubbly face and dishevelled clothes are crisply resolved. These qualities make it much sharper and clearer than even the best portable DVD deck.
But unlike some portable DVD players with lower resolution screens than the source material, the DMP-B15 cleverly sidesteps chicken wire artefacts and jaggies, leaving nothing but wonderfully smooth edges and focused detail. There's a lot more to admire besides, including natural colours, seamless shading, solid contrast, deep blacks and low noise levels. All in all this is a top-notch picture, and when viewed on a full-size TV the images are equally impressive.
Even more surprising is the sound quality from the built-in speakers, which is sharper and more powerful than the majority of portable players we've tested. Yes there's an inevitable bias towards high frequencies but it's impressive by usual portable standards. We'd still recommend using a good pair of headphones though.
As for digital media playback, it handled all the supported formats without any problems but DivX files can look decidedly ropey on the hi-res screen and music lacks oomph through the speakers.
What we love about the DMP-B15 is that it's a top-notch Blu-ray player that just happens to be portable, thanks to Panasonic's generous decision to pack it full of features you'd find on a standalone deck, including BD Live, Viera Cast, 1080/24p output and HD audio support. The non-1080p screen isn't as big a problem as you might expect, as the pictures still possess plenty of hi-def sparkle, and as a bonus it's easy to use and there's an SD card slot on board. The slow disc loading, unremarkable looks and lack of Wi-Fi are the only blots on the copybook - otherwise this is a superb player to take on your travels.