Here we go:)! Everyone's favorite topic....
I think if you buy used, the depreciation hit has occurred. So the make of the car is less relevant than the condition, options, etc. There is a Caterham listed here that cost over $125K new, and the owner wants $69K now, just a few years/miles later, so Caterhams are not depreciation proof.
On the other hand, I bought my used Cat for $22.5K and sold it 4 years & 17K miles later for $21.5K (Let's pretend, for now, that I didn't spend a small fortune on maintenance and up-grade-itis). I bought my 2 year old used Birkin w/700 miles for abt $15K less than it was new. And I believe I will be able to sell it for abt what I paid for the foreseeable future.
Ditto WestTexas's drop dead gorgeous Ultralite that has taken the depreciation hit already, cant go wrong w/it or the other well sorted, debugged se7es for sale.
If you buy new, you can spec the car just as you want, without the compromise on color, features, power, etc., that a used se7ens purchase entails, but you get hammered when you resell.
And, just to be a PITA, guys: look up the meaning of advise(advice) and loose (lose), two of the most misused words on all car forums, not just this one.