I bought FSD last year. (Got no refund and a middle finger from Telsa)
I actually did both.
Bought FSD for our Model S last October for $4,000 ($5,000-$1,000 refund) & $2,000 ($3,000 - $1,000 refund) for our Model 3 on March 1st. So, $6,000 for both cars. In total, exactly what it would have cost at delivery. ($3,000 each) I’m pretty happy overall, even though I would have saved $2,000 If I had waited until March to purchase the FSD on the Model S.
Frankly, I think, if Tesla had just offered a limited time, FSD same as delivery price amnesty promotion, they would have gotten less blowback.