Zing comes in two parts; the Zing Virtual Machine, (ZVM, which is a Java Virtual Machine) and Zing Service Tools (ZST) which is software installed on Linux along with their kernel module that does memory management. As a Systems Engineer I find managing Zing in an enterprise environment very easy.
Upgrading is simple. A ZST upgrade is not needed for every ZVM upgrade - multiple versions of the ZVM can run on the same ZST. ZSTs are packaged in RPMs, so all we do is "yum update" and "reboot".
Planning/Sizing for Zing on hardware is a little different, but still straight forward. When the zing kernel module starts it immediately takes a chunk of RAM, an all ZVM memory allocation is done inside there. There is no risk of other operating system processes depriving Zing Java of heap space, as it's already taken by the kernel module.
Licensing can either be done by a centralised server for all ZVMs to "dial home" to, or a static license file can be stored on the servers.
Early versions (years ago) of ZST didn't upgrade cleanly, we often had to double check that kernel modules were removed from the module tree correctly. However the more recent versions do not have this problem and our management of ZST is a lot smoother now.