I have had a string of S classes starting from 2000, all leases. The current one is a 2011 4Matic fully loaded. The wife is currently driving it.
Since delivery of the MS four months ago, I don't miss the MB for a second.
I do miss some of the features, however. The A/C seat and adaptive cruise are probably the biggest ones. The S class definitely has better seating and fit and finish, but it almost seems like all of what is there is not necessary. Every time I get in the Tesla it feels like a modern experience for me, and all these items that are 'missing' seems less important. I used to leave the MB home when we went to NYC or if their was valet, now I leave the Tesla behind, even though I always want to drive it. Now, when I get in any ICE I look at the controls and think how antiquated it all looks.
As far as value, who knows. If you drove an S class off the lot today, would it be worth the same as a Model S?
We certainly don't buy these things as an investment. We buy them with our heart.
Test drive a Tesla and I think you will get your answer.
Good luck with whatever you choose.