I posted this up in another thread, but just wanted to bring the discussion out here. I haven't had a chance to get my hands on any of these yet, but from what their official videos show, the only thing they offer over last year's is a higher-resolution screen at the cost of a much slower interface.

I count 6 seconds from pressing Pandora on the 5500 and music playing, compared to 3 seconds on the 8400, and station list being virtually instant on the 8400 compared to about 5 sec or so on the 5500. It seems a ton slower than the 4400 as well, so I don't know if that higher-resolution screen has anything to do with it, or if the #500 series of units have something else going on that's making it much slower than the previous generation. Video of the 3500 make it appear that this new generation is all-around choppier than the previous generation. They don't advertise full iPhone5 compatibility either, so there seems no reason to buy these over the last generation of units. Oh, and previously, even the "base-model" 1400DVD could have satellite radio or HD radio through the add-on adapters, now none support the HD radio add-on and only the 3500 and 5500 allow the satellite radio adapter. I *really* *really* hope these units are stop-gap models while they put some polish on their real next-generation models that would ideally have both full support for Android and iPhones running iOS 6, because compared to last year's models, they're a downgrade.