UPDATE: See our full review here:
Panasonic DMP-BD80 Review
We just got the BD80 (DMP-BD80) in for review and so far it looks great. It's basically the BD55 plus VIERA Cast. I played around a little with YouTube last night and it looks pretty good except for not having control over the screen aspect ratio for YouTube videos. But even at Full Screen on a 50-inch HDTV, many YouTube videos still look watchable.
Over the BD55 it adds a USB drive for playback of video files (including DivX) and MP3 songs. I tested this and the player detected that the drive had videos and music on it, and it asked which I wanted to watch or listen to - playback of both types of media worked like a champ. Unfortunately I was not able to zoom in on a DivX AVI file to view it full screen but at least the aspect ratio did look correct (unlike the BD55 which stretched DivX videos horizontally).
For Blu-ray playback, I only watched a little bit of Bolt - the upcoming Disney animation Blu-ray which was giving the BD55 some trouble (on a BD55 with 1.7 firmware). It played back with no problems on the BD80 and the detail and color accuracy seemed on par with the BD55 (though I have not done any real testing yet of video performance).
There is a "Quick Start" option which does consume a bit more power in stand-by but allows the player to boot up faster. Also, there is a new "High Clarity Audio" feature that allows you to disable the analog audio processing if you're only using the digital/HDMI out.
Overall, the menus and operation seem to be very close to the BD55, but with the addition of the VIERA Cast feature for direct access to web-based content. And all at the same exact price point - sweet!
Expect a full review to be published on the site next week.