Assuming you "bought into" the program by paying the financing $600/year for service, which probably adds up to at least $5K.
Some math**:
Tesla financing (US Bank/Wells Fargo): For a $100K list price with 10% down and 72 month term @ 3.5%, the monthly payment is $1387.66. So, 36-39 months of payments = $49,955.76-$54,118.74
Alliant financing (one popular alternative to Tesla): Same conditions as above, except rate is 1.49% => monthly payment of $1307.48. 36-39 months of payments = $47,069.28-$50,991.72
Difference in payments ranges between $2,886.48-$3,127.02
The buyback price formula is 50% of the base price of a 60kWh + 43% of all other options and upgrades... so for a $100k new price, that's 0.50*$69,900 + 0.43*$30,100 = $47,893. The balance on the loan after 36 months is $47,356.90, so if you sell the car back to Tesla, you pay off your loan and have $536 left over. On the other hand, the remaining balance on the alternate loan @36 months is only ~$46,000 flat.
You are right, you've also got to stick to the annual service schedule (but odds are you probably do that anyway) and there is a $0.25/mi fee for miles over 15k/yr. 15k/yr seems like a decent allowance for most, but once you have an EV that can supercharge for free, you may want to drive more.
In the end, the premium of going with the Tesla financing will be about $3k (over the first 3 years), a bit more or less depending on your list price. Is it worth it? As peace of mind, maybe. If you plan to sell your car after 3 years, probably. Otherwise, you can save a bunch by going with the alternatives.
** I'm not factoring in tax credits because the amounts can vary from state to state, and the timing of when you receive them during your financing cycle also varies with when you buy the car and when you file taxes, and when you actually get the money back; and some may not want to throw all that rebate money back into the loan anyway