Upgrades to these machines can occur automatically from then on. Software upgrades are easy and fast. Machines are much more secure and reliable. Security patches can be quickly distributed because of number 3 above. As well, reliability problems can also be addressed quickly because a machine's configuration is in a known state that can be compared to other, working, machines.
All machines contain a consistent set of files.
Since there is a high degree of control over which files appear on a given machine, it is much easier to debug problems. Also, such machines will have more consistent configurations, and thus more consistent behavior. After administrators construct and test a software distribution for a given hardware architecture and operating system, it is simple to add new features. Loading a machine takes only a few hours, and is guaranteed to be a known and tested configuration. There are also ways to add change management systems to our software distribution systems, so that administrators can control the number and quality of the changes that go into the distribution.