A few points of difference if it helps anybody. Tesla provided me with a 75D loaner while my Model 3 was being worked on:
Model S Pros:
* way nicer seats. supportive and sporty and nicer feeling.
* alcantara interior liner is more luxurious than cloth
* steering wheel material immediately feels nicer (real leather?)
* height adjustable suspension could be useful if you drive on bumpy or steep stuff
Model S Cons:
* slower than Model 3 performance
* rear visibility is worse
* steering wheel controls feels dated, as does having dedicated physical mirror and steering wheel controls
Others:
* drove pretty light for a heavier car. but still larger and heavier feeling than 3
* didnt find the portrait-orientation screen, or dual screen useful. surprised myself at how "optimal" i found the model 3 UI...matter of familiarity probably
* self-presenting door handles are uglier, but works better
* center storage bins is a bit messy yes, but still found them capacious and useful
These are all first-impressions type stuff, and nothing to do with prices and warranty and other decision making factors. Though i suspect the PRIMARY one for most people will simply be SIZE-- are you a big-car person or a small-car person? Do you need to haul husky-sized kids/full-sized adults often or infrequently? Do you drive in Omaha Nebraska or Siena Italy?
I'm small-car all the way