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Pros
Pro OSX is developer-friendly
OSX is based on XNU (Darwin) kernel, it's certified Unix and arguably a lot more developer friendly than Windows. Development for Unix is native on OS X.
There's a large selection of great development tools available for OSX. The operating system itself comes bundled with a powerful terminal emulator, called Terminal. Additionally, Apple provides tools, like Xcode, an IDE that contains a comprehensive collection of tools for developing OSX and iOS software, for free.
Cons
Con Low resolution screen
The 1440 x 900 screen is behind the expected 1080p screens of most modern ultrabooks.
Con TN LCD Panel
Being a cheaper variant of MacBooks, it uses TN LCD panel instead of IPS. That means it has worse color accuracy and significantly narrower view angles. The panel only musters 60% of the colours in the sRGB gamut, and falls particularly short in the blue regions. As a result, the MacBook Air's struggles to reproduce a huge swathe of blue shades
Con Comes with macOS
macOS is great for a user that doesn't have much clue about using a computer, but for an advanced user that wants to tinker it tries to hinder you in many ways. To be able to install reasonably newer versions of important dev tools you have to install hacks like homebrew, managed by third partys.
Recommendations
Comments
Flagged Pros + Cons
Con The default OS spies on you
Apple spies on its users, and helps others spy on them too. OSX needs to be wiped from the laptop and be replaced with Linux or another acceptable OS before it can be used.
There have also been cases of security issues being reported and not fixed for quite some time. An example is a security issue in iTunes which was left unfixed for three years while it was being used by the government to collect data. These security issues may or may not be intentional, but other data collection is.