I like exclusivity in the Sub and Daytona... since Rolex does not give the option of putting a sapphire caseback, I am ok with putting my own and if I need, then replacing the original one back.
I do understand a sapphire caseback in a Rolex is not for everyone...I would say it is around 50/50...
When I showed the sapphire caseback to my wife she almost fainted...(never new she was a purist
) but then she said she liked it...so I was safe..