OmniOS
6.5#4 in server operating systemFrom $500 a yearFree planLinuxSelf-hosted
VisitOmniOS suits administrators managing x86-64 servers or virtual machines who need ZFS, containers, virtualization, and signed package updates. It is also relevant to deployments using physical hosts, AWS EC2 images, or virtual machines.
OpenIndiana suits people running 64-bit x86 workstations, servers, or PCs who want a free Unix-like system. It also fits administrators needing IPS package management, boot environment tools, and optional SFE or pkgsrc repositories.