For a full-time developer, I agree with the OP insofar as Linux and Mac are largely interchangeable. I develop on Linux and love it.

The biggest exception is for anyone involved in graphics, front-end development, or often works with graphic designers. The lack of native installation of Photoshop and Illustrator wrecks it.

That's what largely spurred my decision to buy a Mac. There's only one OS that currently offers a Unix CLI with native Adobe Creative Suite installation. If Adobe ever offers native CS on Linux, I'll be Linux for life.