Linux has sandboxing per SELinux. However, SELinux puts the burden of sandboxing on the administrator, or in the case of a desktop OS on the user. Apple, on the other hand puts the burden on the application developer.
Applications have to opt-in for Sandboxing [1]. Once an application opts-in, it has no access to anything but its own home directory. File opening/saving dialogs are handled through the pbox daemon, and are the only manner for the sandboxed process to get access to the 'outside world'. Some privileges like network access have to be retrieved through entitlements.
What we will see is the first, vendor-pushed attempt, to sandbox every application on a mainstream operating system. And it will probably work, because the burden is on the developers, not the users.
[1] Apple will probably make it mandatory in the future for new applications sold in the App Store.