In addition to our comment earlier today about Snow Leopard, John Siracusa from Ars Technica released a deep review of Snow Leopard Mac OS X 10.6. He reviews several important changes/points among them:
Installation
Design
64-bits architecture
Quicktime X, Quicktime Player
Unified API system (to help developers)
Features for developers such as compilation
Management of graphics resources and displaying + OpenCL
Improvement of the dock, Finder, larger support for scanner, improved dialog boxes
Native and integrated support for Microsoft Exchange
No support for ZFS file format
As we already mentioned it, this "0 new feature" update dedicated to recent Mac is a true success for developers and users, even though the latest will have