Isn't this Group Policy or SCCM?

At this point, you may be wondering whether DSC isn't a re-implementation of Group Policy (GPO) or System Center Configuration Manager (SCCM). It's a valid question, as there are some overlaps in these technologies.

Group Policy is similar in that it is also a system of configuring operating systems, applications, and user settings in an environment. However, Group Policy is tied to Active Directory (AD) and has a lot of configuration overhead, a complex and sometimes confusing deployment methodology, and is very inflexible. This is not to say that GPO is bad; some of these apparent limitations are by design. GPO has been around since Windows 2000 days and has had to deal with several decades of different approaches to software and server management.

In comparison, DSC is not tied to AD or a specific operating system platform. It is, by design, very flexible. As we have covered, it is designed to be responsive to the frequently changing technology and dynamic business environments we have today. Instead of obtuse schedules, DSC deployments are declarative and upfront about what exactly will happen and when it will happen. GPO has rudimentary tooling that writes binary files for its configuration that can't be read by a human and can't be version controlled. DSC has human-readable configuration files that are version controllable.

SCCM is also a configuration management system and is a huge piece of software that requires several servers and many hours to set up and maintain. It is not a small expense to purchase and continue to run, and it is clearly designed for a large enterprise that not only manages servers, but also manages user devices such as desktops and laptops. It is definitely an all-purpose tool that tries to encompass any need. Managing servers comes free with PowerShell and requires little setup time. While clearly designed for server management, some desktop management scenarios are supported. It is definitely a fine-honed tool for specific purposes.