Installed 7.0 on my early VIN P85, and after reading all of the comments on the forums, was prepared for a leap backward in the user interface.
However, after using it for several hours yesterday, overall, it is an improvement. Ignoring the flat vs. 3D, the layout is significantly better. They eliminated the frames around the windows in the main display - which seemed to be an attempt to match the frame for the 17" display. And they eliminated the rounded status boxes the filled the top and bottom of the dashboard. Both of these were unnecessary, used up valuable display space, and actually degraded the perception of both displays.
The new interface seems to have better contrast - many of the elements seems to be crisper and easier to read. And, with the map displays, they have the map displayed in the background on both the dashboard and console so that the map is visible underneath other objects being displayed.
Since I have a non-AP, early model, P85, I still have the original speedometer, with the small car display replacing the battery. I don't mind moving the battery display to the lower left - though the small car really displays little valuable information. While it's cute that you can (almost) see the brake lights and the headlights - that's really not very useful. The brake lights are harder to see - and if they really want to continue with this, would probably have to make them more visible - plus, there should be an indication of when the bright headlights are enabled.
However, I'd rather they use this area for something more interesting. For example, something that would be extremely useful - and is still missing is an indication of the air suspension status - I would like to know when the air suspension is low and when it's being changed automatically - without having to bring up the air suspension display on the console.
The new trip display isn't particularly useful. Like the new clock, both of these display relatively little information. What would be better would be a status display that could show digital time and outside temperature, the current trip usage information and along the bottom of the window the energy usage display. All of this should be able to fit into the area on either side of the speedometer.
The biggest disappointment is how little has been done to provide any real improvement in functionality. While I believe the new UI does look better, it really doesn't provide much additional information, and what I am still waiting to see is new features - that should have been in the software by now. Items such as playlists for media playback, improvements in the navigation software, providing a display of the speed limit using the map database for earlier model cars, the app store with 3rd party apps, ... The navigation software still underperforms especially with the constant access to the Internet - features that would be extremely useful include real-time updates on upcoming traffic issues, waypoints, customization of the planned route, information on upcoming POIs (restaurants, shopping, ...).
And the software still appears to have some of the same problems that were there with version 6. The album art still doesn't display reliably. In the turn list for the navigation software, it doesn't provide the correct name for the upcoming turns (such as exit names from highways). And the navigation software still thinks it takes 5 minutes to drive the last few houses on my street to get to my house.
Yes, getting the AP working is important, as is continuing to push the envelope on a self-driving car. But there will be increasing disappointment with the onboard software if Tesla doesn't start investing more in providing more complete implementations of the software after it's been released. Other cars are getting the Apple and Android integration - in the Model S, we still don't have integrated text messaging...
Hopefully now that V7 has been released - Tesla will invest resources not only to refine and improve the latest UI - but also to address the long-missing features from the rest of the software...