The Ubuntu Linux family has many versions to choose. This includes, Ubuntu-Gnome, Ubuntu-Unity, Kubuntu, Xubuntu and Lubuntu. All versions are free to download and distribute. There are also offshoot or modified versions of Ubuntu such as Linux Mint and Zorin OS.
These are considerations for choosing: Unity and Kubuntu are graphics intensive, meaning these are not recommended for older or slower machines. Kubuntu probably resembles Windows 7 the most. If your machine runs Windows 7 then it should run all versions of Ubuntu. For older machines I currently use Lubuntu although this is not recommended for new users as Lubuntu requires modifications to be fully functional.
Linux based operating systems offer many choices so be sure to check the appropriate help forums and TOTAL OS TODAY for help in using and maintaining your Ubuntu system or systems.