If you have one and an X, what do you prefer and why? Is it a HUGE difference between the two? 2015/2016 doesn't seem like the quality will be night and day but I could be wrong.
Between my wife and myself, we've had (oldest/cheapest to newest):
2014 Model S 60 RWD inventory (non-tech package, no parking sensors, no turn-by-turn nav)
2014 Model S 85 RWD CPO (
wife's current car, has tech package w/nav + park sensors, she loves it, pre-autopilot)
2014 Model S 85 RWD inventory (was my first car, before AWD and AutoPilot hardware came to exist)
2015 Model S 85D AWD inventory (owned for about 16 months, loved this car, first AP1 car)
2016 Model S 70D AWD custom order (facelift, which I'll talk about more in a second)
2016 Model X 75D AWD inventory (
this is my current car, sold my face lift my Model S for this beast)
For me it was a matter of trading first because I wanted AWD/autopilot, second time because I wanted to downgrade (lower payment) and the facelift. And third time because I wanted the SUV, and since my wife had the sedan still, it gives us the best of both worlds.
That said... the face lift DOES add a few features. Not only did they revise the aero slightly (~3% better coefficient of drag by redesign of the front fascia and rear lower valence), they made some smaller improvement. Perhaps the best one I noticed was the front radar being hidden behind the bumper. My 2015 AP1 85D had issues during increment weather where snow build up on the low to ground location caused AP to stop working on some trips-- had that issue almost never on the face lifted car. Also the face lift car has better headlights even w/o the premium package, but add premium + face lift and you get adaptive headlights I believe (mine didnt have PuP).
Interior materials were slightly improved in the later cars, each year they get a bit better. Latch on the frunk is improved on later cars versus earlier cars. Revision on the door handles is better (though if you have warranty not a huge issue, but my 2016 never had door handle replaced-- on our 3 2014s and 1 2015, all of them had at least one door handle replaced over time due to motor/actuation issues-- again by late 2015/early 2016 they had fixed those).
That said, I'd also personally get the face lift because then it will "look current" for longer. At this point the old fascia nose cone is already the "classic" style and out-dated. If you can get into a face lift car for the right price you'll be getting the "current" aesthetic. Not saying that is a big deal-- and yes, 2015 build quality is solid. But newer might keep you happier longer to have the "new" look.
As for S vs X ... personal preference. The X just feels huge to me, purposeful to drive, but at these same time, almost too big much of the time. If you could have only one, and you didn't really next 6/7 seats-- the S is hands down better due to the size, range, efficiency dynamics, etc. However, there are so many cool unique features of the X (auto open/close front doors, FWDs, etc). I will also say that hauling "items" (large/long) easier to do in the S with the rear seats folded down. Even in the 6 seater version the X is better at hauling people than it is hauling stuff. We have a '14 S non-AP so we use my '16 X to do long trips. But daily, to work and back we drive the S because its just easier to "bum around town" in.
Hope this helps!!