I mostly like their use of an immutable OS as base layer for the virtualization - despite the limitations it sometimes has.
I remember since the start that SUSE was more popular in Europe, but no way would that be the case in the US. If anything, I’d be willing to put my money on > 60% of Linux installs being RHEL/Centos rather than SUSE
Also, from my own experience, SUSE used to have nearly all of the US geointelligence processing because of the HPC connection mentioned elsewhere with CrayOS, but that went away when DNI forced everyone onto the CIA's private AWS service, which only had RHEL AMIs available. The national labs and more niche intelligence processing that can't run in the kinds of machines AWS provides still make heavy use of it.