Not to mention the build quality of a MacBook is unlike anything I have seen. The quality, design, usability, etc. I dont see how anyone in the IT field can spend some time with one and not appreciate how well the entire package works. There is such a tight level of integration between hardware and software on a Mac. Windows machines just dont have period. Can you buy HARDWARE of a similar sped for less money? Yup. It wont be so tightly mated with its OS though, and thats the biggest drawback, and one of the main reasons I guarantee you moving forward that Microsoft puts out more and more of its own hardware.
IT people like the ability to repair computers on site.
I tried to join one of those Macbook Airs to our AD domain and found out that it's broken (as in a bug). So much for it just works.