For years Citrix XenApp (the new name of Presentation Server http://www.Citrix.com/XenApp) customers have been using XenApp, as an application delivery solution, each year, getting more value as Citrix continually improves and adds more functionality as the needs of users increase. (To learn what Citrix is doing for the next release or XenApp, refer to project Delaware http://www.Citrix.com/Delaware).
These customers understand the relationship between XenApp and Terminal Services and how together they provide a powerful solution. A question I often get asked is; do I see a day when the functionality of TS will be enough that the need for XenApp will be lessened? Some customers expect this is just a matter of time and assume one day Terminal Services will be enough.
The simple answer in my view is that TS will never be enough, because the good enough bar continues to move up. The good enough bar is the level where a customer is comfortable with the functionality that they are prepared to accept that level of functionally, usability, security etc, is enough for their organization.
To correctly answer the question you need to ask what is good enough? It is a different answer for different organizations. It's not just a matter of size or even complexity but it's about what dependency the organization is putting on the overall solution and how does an organization see this changing over time.
Also if you asked what was good enough in 2003 and what is good enough today you will get a very different answer as organization's needs have changed in so many different ways.
This change in what is good enough, the changing levels of the good enough bar, is due to a number of factors:
IT has become more critical, and many would not survive today without their IT systems and for some, IT is extremely strategic and is a competitive weapon.
IT has also become much more complex, with all business processes now automated and each linked in some way. Security issues have also raised the good enough bar, organization are looking for the most secure way to provide application access to users.
Users needs have also become more complex, using many more applications; they are much more demanding, expecting to have access to their systems all the time.
Applications themselves are also more complex, and there are multiple generations of application types with organizations.
I'm sure there are a number of other factors you could add that continue to drive the good enough bar upwards.
Finally this is not a static environment, the good enough bar of tomorrow will be much higher than today.
Understanding that the good enough bar is always changing you can understand why I would say that TS is not good enough even with the new features of Terminal Services in Windows Server 2008 ( http://www.Microsoft.com/WindowsServer2008 ), because organizations are not prepared to take a risk and deploy a system that could be otherwise improved by adding more value.
Citrix XenApp uses the Terminal Services platform to provide the most complete application delivery solution with the best, centralized control, application compatibility, optimized user experience, comprehensive access and scalability.
As more customers realize the enormous benefits of this new model of computing; delivery all applications anywhere to their users; they will want the best possible solution, one that has the most complete set of features. A solution that has the best chance of being successful today and also adapt to their future needs. Whether an organization is deploying a few application or all their applications, they should look at the most complete solution knowing they will end up with the best end result.
Then there is the question of cost. What customers have found is it takes less time and resources to deliver a solution that is more complete, that works as a complete system, than try to piece bits together, this weighed with the risk factors shows it's always better to start with the most complete solution the 1st time rather than add functionality later. There are too many other things that need to get done, why take the risk?
Organizations that have been using XenApp for more than 6 years know this question has come up each time Microsoft releases a new version of Windows Server with added Terminal Services functionality. To date this has been with Windows NT 4.0, Windows 2000 Server, Windows Server 2003, and now with the new Windows Server 2008. So for all of theses and for the next release of Windows Server the answer is 'no' TS is not good enough because the good enough bar continues to move up!
To understand more about XenApp and Terminal Services, I would refer you to another blog by Bryon Thomas on Terminal Services and XenApp, Bryon lists a number of tools available that list the enhanced value of XenApp and he is asking for suggestions on what other tools are needed. ( http://community.citrix.com/blogs/citrite/bryont )
I welcome your comments and views on the concept of the good enough bar, how is it rising in your organization?
Nabeel Youakim
VP & Product Line Executive,
Applications Virtualization Group, Citrix Systems
Posted by 
Nabeel, great article!
It couldn't be any clearer that XenApp (formally Presentation server) adds tons of value to Windows Server TS and will continue to do so for the next releases.
Just sharing a few thoughts here:
Windows Server 2008 offers Remote Apps (seamless), Web Access (Web Interface), TS Gateway (Secure Gateway), along with a few others.
Now if you look at this closely, Citrix has been offering these features since early version of MetaFrame, and to in order to take advantage of these few features on WS2008 the client much have the following components installed: Windows Vista SP1 or Windows XP SP3, IE7, and RDP 6.1. These are some pretty hard requirements to fulfill, never mind the fact it doesn't support previous versions of windows nor other operating systems; I would say it's pretty hard to convince any major company to adopt this technology while imposing them to migrate their entire client workload the latest client platform, and keep in mind some of them are not even released yet (I.e. XP SP3).
I don't want to get on all the benefits XenApp currently adds to WS2003, we are well aware of them; also knowing the feature set that's going to ship with Delaware we can all rest assure that no one is going to be questioning if XenApp adds value to the lastest Microsoft platform.
I posted earlier this month a live lab where people can login into a live WS2008 Terminal Server and play with its key features, it was very easy to setup this environment, but unbelievably the hardest part is to find someone who can comply with the crazy client requirements in order to launch a simple seamless session.
If you meet these client requirements and you truly want to compare apples to apples you can give it a try here: http://www.frameworkx.com/newsdetail.aspx?tag=121&c=1093. I've been using it for awhile and I can attest that my Citrix environment is far more complete then my WS2008 TS farm.
Now I'm not saying WS2008 TS doesn't have a place in the market, it surely does, in fact it raises the bar for our entire industry, but if you want to get the best experience on application virtualization you can't seriously consider a singular install of the product.
The Delaware release simply shows that Citrix continues to innovate and strive with its app virtualization platform.
Regards,
Gus Pinto