Performing an upgrade from Mac OS X 10.5.8 to Mac OS X 10.6 Snow Leopard Build 10A432 on a MacBook Unibody 2.0GHz. Overall Snow Leopard looks exactly the same as Leopard.
However, the disk capacity clearly benefited with an improved filesystem.
Users will have close to the disk capacity they paid for.
The new filesystem on Snow Leopard is clearly evident. After the upgrade, the capacity of the 500GB shows 499.76GB instead of 465.44GB