A friend of mine who has a relative that works at Tesla took delivery of his 3 last week (VIN 800s).
Build Quality:
It’s nearly perfect!! The panel alignments are perfect, everything is sturdy and clean, the seals are also pretty good…but still slightly bent in the top corners of windows, not really a big deal. Much better than 57xx Model X…and this car is in the 800s!!! The seats don’t have any wrinkles, and they aren’t any rattles!
Space
The car has a lot of space! The trunk is huge, rear legroom and headroom is not as much as the 6-seater X but still really good. The center counsel is awesome!!
The Screen
Coming from the X, it will still take some getting use to. The UI doesn’t seem entirely finished as certain tasks are still not-intuitive but it is still responsive. I still prefer the X/S screen layout but this is still pretty good. Also, it seems that they need to fix the auto-brightness.