Mac OSX (client) and Mac OSX Server (10-client) and Mac OSX Server (Unlimited client) are fundamentally the same software.
Mac OSX (client) is "crippled" from the full-featured one.
It's silly to attack Windows 7 based on the business model, when Apple is doing the same thing (just fewer tiers, that's all).
Windows 7 Basic is built on top of Windows 7 Starter. It is additional functionality, not present and crippled.
Windows 7 Home Premium is built on top of Windows 7 Basic. It is additional functionality, not present and crippled.
Windows 7 Professional is built on top of Windows 7 Home Premium. It is additional functionality, not present and crippled.
Windows 7 Ultimate is built on top of Windows 7 Professional. It is additional functionality, not present and crippled.
Windows 7 Server (Win2k8R2) is built on top of Windows 7 Ultimate. It is additional functionality, not present and crippled.
This is clearly a glass half full or half empty situation - are features added to the bottom, or subtracted from the top?