If you are a picky person, you might not like fit and finish quality.
I got Model S in 2012 and most people has not noticed uneven body panels and trim. When I pointed them out, they are like me: no big deal, not noticeable unless you are an expert.
My 2017 Model X panel, trim and paint quality are much better than the 2012 Model S.
I haven't gotten any minor or major issues with 2017 Model X so far.
For my 2012 Model S, I saved all my minor issues until I drive long distance to a Tesla Service center for an annual check up. They also applied Service Bulletins and proactively swapped out suspicious parts as well. With the latest 87,500 mile inspection, they swapped out my drive unit (
$18,000) for free after they test drove my car and said the hum was louder than usual and I could still drive for many miles after warranty runs out but it doesn't hurt to be proactively so we won't have to deal with a 200 mile tow (one way distance, 400 mile round trip for purpose of tow fee but it's free for up to 500 miles) from my town to a Service Center.
An example for Model 3 fit and finish concerns shown in
Pictures of production Model 3s
I have been very satisfied with Tesla performance, durability, quality, service... since 2012.
My only gripe is I wish there's a Service Center near my town.