Buy the S. At the 79k price there isn't a better value in the Tesla lineup. I loved my Y but the S is SOOOO much better it isn't even in the same league. You get a huge trunk, better seats (and cooled), nice interior by far, homelink standard, larger screen and the list goes on.
I will and am looking forward to getting my S!
BTW, I was seriously considering getting an X instead of an S because people told me that is a no-brainer to get an X instead of an S. They also told me all of their friends regret getting Ss instead of Xs. After the detailed discussion with DayTrippin and his insightful explanations (highly appreciated!), I believe currently S is a better choice for me and I will love it!