Dramatically. You can lock down just about anything in the hardware and software on client Macs. Browse Apple's OS X Server pages, you'll be amazed at what you get for $500 for 10 clients, $1,000 for unlimited.
I am not just talking about lockdowns. How familiar with AD are you? Advanved GPOs and such? Can you, for example, offer support to a mac station from your mac station, which shares his desktop? Can you control what type of cetificates the workstations will accept? Are there millions of options?