Ubuntu is a preferred desktop OS, that uses the Linux kernel, and its server version is getting pretty popular too. The reason is that the operating system is very light and it will function on almost any hardware without issues, utilizing its resources to the maximum. Ubuntu is also pretty reliable and secure and all of the Long-Term Support (LTS) versions are supported for a minimum of 5 years, which guarantees that you will have a protected and dependable software environment on your server all of the time. Furthermore, Ubuntu has one of the biggest user communities globally, which means that if you experience any problem or have any kind of question, you'll find lots of resources on the net. One of the main benefits of this OS is that it has tens of thousands of software packages that can be freely changed in accordance with your needs and the requirements of the apps which you'd like to run, not to mention that you won't have to pay any kind of license fees at any time. In comparison, other Operating Systems are paid and their code is not accessible, therefore it can't be changed.