We're in the process of setting up a Mac Pro Server now. The IT guy said he'd rather leave Tiger on now (he'd install it if I really wanted him to), and wait a while until switching over to avoid any issues since is a brand new OS. Since the Mac Pro was bought in Oct. I can get the 9.99 copy. I'm following his advice because he's the expert. I'd imagine all Mac Pros after the release will have Leopard running in them. Would you trust your Mission critical data to a new APPLE OS? I know I'd never would with anything with Microsoft without a long wait for service packs. Are we missing anything important in Leopard that would warrant taking the risk of using it at the start?