I haven't used it as much over WAN connections but I am familiar with Teradici's efficiency over slow links. In our LAN, environment, the best feature is central management and small footprint. These primarily go into lab, testing and kiosk areas due to minimal hardware outlay and easier to lock down.
Remote Desktop Services provides access to work environments from any device. This allows us to ensure business continuity in case of disaster. It provides admins more control over access and security. Remote Desktop Services simplifies software updates and compliance management by reducing the need to act on end users devices.
When you connect with RDS, everything looks and feels (and is) exactly like you're sitting at that desktop. This is great for us and for users.
You can sign in with RDS and the desktop will be the same as when you left it (if you choose to set it up that way).
Although they take some setup, RemoteApps are a very handy way to let users access a program without requiring them to actually connect to a remote desktop on the server.
Remote Desktop Services currently does not support multiple monitors on the terminal server. Unlike other applications such as Teamviewer, there's no feature to toggle between multiple screens even if they were connected to the terminal server.
Remote Desktop Services should provide an option to scale up or down the screen size after a connection is established. Currently you can only adjust the screen size prior to a connection is established. So you'll have to take a best guess at what display screen resolution will fit best on your screen.
Remote Desktop Services should offer some kind of menu to send special key strokes like Ctrl+Alt+Del to the terminal server. Currently the substitute for that particular combination is Ctrl+Alt+End. But I have yet to discover a replacement for other combination keystrokes such as Alt+PrintScrn.
The initial setup for Remote Desktop Services is complex, and licensing is costly. Each user connects to their virtual desktop hosted by a single server or group of servers, so a change or issue with servers quickly impacts every single user at the same time. Aside from that, users appreciate seeing their same personal desktop from any device or geographical location.
As with any Microsoft Server product, support for Remote Desktop Services requires a paid support package. These are license-based and very costly, on top of the already costly product licensing. Microsoft's licensing is complicated to begin with, so setting up licensing alone essentially requires a licensing expert's counsel. There is community documentation and support available on Microsoft websites, as well as community websites.
VMware Blast! is now VMware's standard for VDI. It has some features that make it better in a VMware environment. Existing PCoIP systems we have are Teradici-based so I am glad that standard is still available. When it comes to hardware, Teradici is still the most available so we continue to choose them.
We selected Remote Desktop Services based upon price alone. Other solutions on the market are significantly more expensive, but if your company can foot the bill you should seriously consider products that have been on the market for longer. The lack of an ability to easily upgrade farm servers has been a challenge for us - although it is still faster than updating an application on 2000+ machines. The lack of a centralized management console in 2008 R2 is also challenging, but you get by with the tools available to you. If you don't have the money to spend on Citrix or VMWare Horizon, Remote Desktop Services is a decent replacement.