Why I love Linux
Linux enjoys all the four freedoms envisaged by GNU. You can freely use it, modify it (since you have its source code freely available) and redistribute it as modified with the same kind of freedom enshrined in it.
Source: “Going GNU“
It is one of the fastest and virus free operating system. No need to buy as you can get it from open source.Its very good for server use.The main problem is you can not install .exe files.