Microsoft RDS:
Microsoft provides a feature that is built in to every Windows Server operating system called Remote Desktop Services (known as Terminal Services in Windows Server 2008 and earlier).
RDS is Microsoft's technology to support thin client computing, where Windows software and the entire desktopof the computer running RDS, are made accessible to a remote client machine that supports Remote Desktop Protocol (RDP). With RDS, only software user interfaces are transferred to the client system. All input from the client system is transmitted to the server, where software execution takes place.
Citrix XenDesktop:
A similar but standalone product called XenDesktop (replacing Metaframe) is available from Citrix if you need more advanced functionality than Microsoft's RDS. Some version of this Citrix solution has been around for much longer than RDS. In fact, Microsoft RDS was initially built based on Citrix technology, before they developed their own protocols.
The core functionality is largely similar to each other. The primary benefit of Citrix XenDesktop over Microsoft's RDS is better support for audio, video and graphics. Citrix XenDesktop is more powerful and used by organizations requiring more fine grained control over the virtualization experience.
See our recommended hardware specifications for your RDS or Citirix server, check out our other article.
