I would think many people buy them for the OS and advanced design. They are also great for artist's looking for the creative edge in terms of software/hardware integration. As an artist, I wish I would have paid more attention when I had an Apple Lisa but the fact is, I became comfortable with other software.
In my opinion, they have the best retail/commercial desktops. They me be more money but their attention to detail and quality components are premium. I have always admired their hardware design and chassis. Furthermore, I think their laptops are second to none.