16610 IMHO is the nicest case design of the modern Subs - better than the ceramics.
But who knows where prices will in 20 years. From my experience My Tudor and Rolex watches appreciated nicely between the seventies and recent times, and a 16610 also appreciated slightly from 2006. But I have always had my Rolexes serviced 5 yearly by Rolex which affects return. But I did all that before joining the forum - I just enjoyed them...
ATB
Jon