HDD Navigation System and Display Sytem

Was on the Toyota website, and there was a long video presentation on the Prius single CD nav system that covers the full U.S., but data is done using regional subsets (southern california and Arizona, etc. are in region 2). The video also showed a bit of the voice commands. Searching through this forum, I thought I'd read that the 7.1 HDD is a different Nav system and has less voice commands. Is this true? What are the differences between the old and new Nav, besides the larger screen, and less use of the phone's data allotment?

As I understand it (correct me if I'm wrong), the new display system uses it's own internal electronics to access directions, real time traffic, access to points of interest (via BING) and does not use your phone's capabilities via Bluetooth. You'd only be using your phone for calls which you can do via voice commends. Do I understand it correctly?

Those of you that have the new 7.1 system, how do you like it?

Thanks in advance for all info on this. We're buying a car late this summer (Prius IV with Solar will probably be the car), and we won't to make sure we do buy what is the best fit for us.