I’ve been mulling over the same issue – but without the nice graphics -when it comes to desktop and application virtualization, and I’m very keen to dig a bit deeper into the user experience impact of a collection of new technologies:

1. Virtualised applications add a small performance overhead
2. Streaming virtualised applications adds a significant overhead to launch time, especially in a VDI environment where caching is of limited value (although pre-caching in the image would be better)
3. Virtualization of the applications configuration and the users personalised settings adds a further overhead to launch times
4. WAN access to data adds a further overhead to application launch times
5. We’ve yet to quantify for many niche applications whether non-persistent VDI images (where only the roaming profile is persisted at logoff) are going to be slower, maybe because they cache for performance in the local profile and assume that the users local profile is going to be there tomorrow 99% of the time
6. Sharing server resources across many users, is likely to work out great on average, but I’m not 100% sure that it will be faster for peak CPU periods which often occur at application start-up
7. Most VDI deployments encourage users to logoff frequently and that’s likely to increase as the logon/logoff cycle is required in order to update the master image, not only does this affect a few of the points above, but it also makes detailed user state preservation very important – ie saving which applications, files, scroll locations, browser tabs, window positions etc the user has open and restoring them when the user logs back in. 
8. I dread to think how regular logoffs would impact my productivity, right now I logoff once ever couple of weeks, and it takes me at least 20 minutes to close everything down and open everything up again, if I had to do this every day – the least of my worries would be the time it takes for the OS to boot.

So one things for sure, in the new word of desktop, end user experience performance monitoring is going to be pretty important.

What does the maze look like?  Well I’m not able to talk in detail about that right now, but Brian Madden sums up the situation well:

Ten years ago it was easy. We only had two options: Citrix (the new way), and traditional installs (the old way). But in 2007 we have application streaming, virtualization, and isolation; VDI- and Terminal Server-based server-based computing; local installations, local streaming, remote desktops, remote isolation, OS streaming, OS isolation…. the list goes on.

The one question I’m asked again and again is, “With all of these different methods of deploying apps, how do we figure out what we should use in our environment?” (The second most frequent question I get is, “what’s real and what’s not today?”

We too are trying to answer these questions, not just on a per application basis, which is the focus on Brian’s article, but for a customers entire application portfolio often numbering several thousand applications.  We’re also trying to ensure that our focus is not just on a point in time, ie we are trying to lay out a roadmap for change, that reflects the business, web 2.0, enterprise 2.0 and consumerization trends as well as the improvements in legacy application delivery technology.

We’re doing the work in the wiki that I posted about yesterday.

Windows Server 2008 is looking very cool for a home lab,  with the ability to publish terminal services sessions over HTTP to the Internet, Seamless terminal server windows, multi-volume disk encryption (finally a secure home environment).