The Panasonic DMP-BD15K is the first portable Blu-ray player, and at first it's easy to write it off as useless since much of Blu-ray's visual superiority doesn't translate on its 8.9-inch screen. But that's missing the point. If you're a home theater buff with a growing Blu-ray collection, you might be frustrated that you can't watch those movies on a plane or even in your bedroom.
The real niche of the DMP-B15K is allowing you to watch your high-definition discs in more locations (rather than making the immersive Blu-ray experience portable), and the DMP-B15K is well-suited to the task. It has a full suite of car accessories and an HDMI output that makes it easy to use as a standalone player, too.
However, like many first-generation devices, the DMP-B15K has plenty of caveats--a bulky design, short 2.5 hour battery-life, and less reliable playback than standalone players. Even more crippling is its sky-high $800 list price, making it only slightly cheaper than entry-level Blu-ray-equipped laptops.
Ultimately, we're onboard with the idea that there's a need for a portable Blu-ray player, but, unfortunately, the DMP-B15K's price and shortcomings make it difficult to recommend to all but the most well-off Blu-ray fans.