Despite being a big fan of opensource and how much I love Linux I think a OSx machine is far more productive, for these reasons:
* It just works. I am well aware that linux is way better than 5 years ago and works just fine on most systems, but I am yet to not need some sort of tweak and configuration to run Linux on a laptop, to the Linux is defense considering that number of target platforms it is inevitable.
* Adobe creative suit. Yes, there is alternatives, inkescape, gimp, and others but they're still way behind.
* It's still nix. I am not going into technical difference or the background and what not, from a users perspective, I can install Homebrew and use most of nix tools.
* More visualization options You can't visualize OSx on Linux or Windows for legal and practical reasons but you can still run Windows and OSx on Mac.
Obviously these are mostly only an issue if you are involved with front-end development where you need design and cross-browser compatibility tests and such, if you're doing only back-end, Linux works just fine once you get it run and learn to stop spending time to tweak it.