Project Atomic integrates the tools and patterns of container-based application and service deployment with trusted operating system platforms to deliver an end-to-end hosting architecture that’s modern, reliable, and secure.
For the Red Hat family members Fedora, RHEL and CentOS there are independent Atomic releases. If you are familiar with one of these you can use them as an Atomic host as well. The Atomic Host Red Hat replaces yum with the rpm-ostree which is used to manage the OS packages with atomic updates which means you can rollback to a previous tree. Also you can create your own custom images for Atomic with the rpm-ostree-toolbox.
One major benefit of Project Atomic is the mature environment of Red Hat. You are able to use tools like SELinux, Kickstart, Anaconda etc. on your Atomic Host.
When I tried their quick start guide at first it didn’t work because it pointed to an old version of Atomic. After I downloaded Fedora Atomic however the I got it running.