If you want a system which is open source in nature, then I suggest you use Linux as it comes with free and lots of open source software. But for the office environment, you better go with Windows OS (windows 10 sucks) as it provides enterprise level office suite software. On the other hand, Mac OS is suitable for high-end media or graphics tasking like Web-Design, UX&UI Design, Product Design, Sound Editing, Image Editing, etc.