Gentoo is a Linux-based, source-based, rolling release distribution that is highly configurable, optimized for performance, and secure. It is optimized for advanced users and developers. It is a popular choice for server hosting, embedded systems, and other high-performance computing applications due to its flexibility, speed, and low overhead. Gentoo is designed to be incredibly modular, allowing users to install only the components they need. It supports a wide range of architectures and can be easily customized to suit any specific use case. It is highly customizable, with its ports system allowing users to compile the software they need in the specific version they require, with any desired optimization flags. Gentoo provides multiple ways to install and maintain the system, including a graphical installer, a command line installer, and a web-based installer. It also provides a set of tools to help users manage and maintain their system, such as the Portage package manager, the equery package query tool, and the emerge package update tool.
Gentoo is primarily for experienced Linux users and is source-based, while Ubuntu is aimed at newer users and uses binary packages.