Arch Linux is a Linux-based operating system for i686 and x86-64 computers. It is composed predominantly of free and open source software, and supports community involvement.
The design approach of the development team focuses on elegance, code correctness, minimalism, and simplicity from a developer’s standpoint rather than a user’s standpoint. A package manager written specifically for Arch Linux, pacman, is used to install, remove and update software packages.
Arch Linux uses a rolling release model, such that a regular system update is all that is needed to obtain the latest Arch software; the installation images released by the Arch team are simply up to date snapshots of the main system components.
In my experience, Arch has the biggest and most active community base among other Linux Operating Systems. They has a very active forum called Arch Wiki, which is fed by many Linux experts all over the world. And you can easily install any package with pacman, Arch package manager, without worrying about repositories or dependencies, as they will be handled by pacman by itself. You can use packer, which is an extension for pacman, which will automatically download the program source code from Arch repositories and it will be compiled and installed according to your computer and its architecture.
Currently Arch can work smoothly on ARM devices as well. See here for more info.
There are much more specialties in Arch Linux and I’m hoping to bring you as best as I can.