My brother currently owns a Model S which isn't a bad car by any means, but from what I've seen, it has gone through a terrible QA by Tesla (door panels not placed perfectly, shoddy mechanical door handle breaking, forgetting to re-enable a door after servicing). Considering Tesla is already running into production issues, I hate to see what QA issues the Model 3 will run into.
Tesla has missed on pretty much all of their goals, but this is a big one. They had predicted production of 1,500 units.
If they want to enter the low cost commodity vehicle business they will have to get a lot better at executing.
I saw a Model 3 'in the wild' here in Chicago 2 days ago - did not realize it was one of only 220 made so far though!