Kubuntu is an official flavour of the Ubuntu operating system which uses the KDE Plasma Desktop instead of the Unity graphical environment. Developed by Canonical Ltd
License: Open Source
ReactOS is an open-source operating system aimed at being compatible with Windows applications, making it ideal for users needing a lightweight alternative for older hardware. In contrast, Kubuntu is a full-fledged Linux distribution that offers a user-friendly experience and extensive software support, making it suitable for everyday users and developers.