The Best-Known & Most-Used Free Open-Source Operating System. Just like Windows XP, Windows 7, Windows 8 and Mac OS X, Linux is an Operating System, but the main advantage of Linux that it is “Free” and Reliable. After long periods of testing, most Linux users conclude that Linux is not only as good but in many cases Better and Faster than the traditional solutions. If Linux were not trustworthy, it would have been long gone, never knowing the Popularity it has now, with Millions of users. Now users can influence their systems and share their remarks with the community, so the system gets better and better every day. It is a project that is never finished, in an ever-changing environment, Linux is a project that continues to strive for perfection.