@Dashrender said:
If you're looking to do a VDI install, buying an Enterprise Windows Server license will likely cost you WAY less (unlimited windows server installs)
That's why the DataCenter licensing (unlimited VMs per CPU) is popular as a VDI substitute. However not all software works correctly if it detects a server OS (AV often does this, for example.) And the per CPU licensing can make for some expensive mistakes as you are pricing on compute capacity instead of by the instance.
And once you get pretty large, you probably want some nice web gateway or other handler to improve the performance or ease of use. And that's when RDS hits you because those extended features come via the RDS packages. So if you are doing a small VDI setup for a few users, DataCenter licensing might work out for you. If you are looking to do an enterprise VDI deployment, actual VDI is probably actually the better way to go.