The set of virtual desktop system enhancements Citrix Systems announced this week is unusual not for its timing or technical acumen, but for focusing on the experience of actual end users. Analysts say that IT knows the user experience with desktop virtualization is absolutely critical to success.

"We did a study that came out just before VMworld [in August] that showed the quality of the user experience is the top criterion enterprises use to evaluate virtual desktop infrastructures," says Andi Mann, head of systems and storage-management research at Enterprise Management Associates.

Asked to rate the most important factor in choosing a desktop virtualization system, out of 10 options, 75 percent of companies chose "Ease of use for end-users."

"The end user experience is critical, and there are some really clever things in what Citrix is doing address that -- multiple ways to deploy desktop services and to improve performance enough to fundamentally improve what the users are actually doing," Mann says.

Citrix's New Improvements for End Users

The improvements - in load-balancing at the server, support for graphics and peripherals at the client, and an additional way to virtualise a desktop application - come free for customers with existing enterprise license or automatic-upgrade contracts.

The most notable new feature in XenApp 5 Feature Pack 2, which is free to customers with enterprise licences and upgrade-by-subscription plans, is VM Hosted Apps. The feature allows Citrix customers to run desktop applications on a separate virtual machine that runs on a physical host running XenServer.

Most desktop applications running under XenApps run in parallel on a Windows or Xen server. XenApps clients connect by logging in to the server and using software already running on it.

With Dynamic Application Delivery, a single application or a specific user's whole suite of applications run on a VM without having to share resources, and without having any difficulty identifying the hardware or operating system on which they run, according to Alicia Rey, product marketing manager for XenApp.

"That's actually a big deal because there are a small percentage of applications, maybe only five to ten percent, that you wouldn't even think to run on XenApps," says Ben Kohn, senior systems architect for Independent Bank, an Ionia, Mich.-based bank with 1,200 employees, 90 percent of whom are connected via Citrix virtual desktops, accessing software running mostly on VMware servers.

"Adobe Acrobat, for example, installs a service that checks on the hardware you're running it on so you don't move it around to different machines," Kohn says. "You couldn't put it on Citrix server or do app streaming with it, but you could install it on a VM and deliver it that way and still use exactly the same infrastructure you would for any other app."