Desktop virtualization has a predicted growth curve that leaves much of the PC and IT services industries smiling: Yet none of the technologies or \n\nservice providers promising to offer hosted virtual desktops are ready to step into key roles in enterprise IT infrastructures, according the same \n\nwell-respected analysts who set the server virtualization market on its ear with a similar conclusion last year."Very simply, none of the hosted virtual desktop providers can match the requirements for the enterprise," according to Chris Wolf, infrastructure \n\nanalyst at The Burton Group (purchased recently by Gartner) who presented a critical report (registration required) at last week's Synergy Citrix conference in Las Vegas. Both Citrix and VMware are prepping versions of their products that do satisfy Burton Group's requirements in storage, infrastructure, management, \n\nperformance and other characteristics, and both are fine for department-level deployments, Wolf says. No Shipping VDI Makes the GradeBut no shipping VDI product set is ready right now for large-scale deployments, Wolf says. The report, which Burton presented at the recent Citrix Synergy end-user conference, looked specifically at Virtual Desktop Infrastructure (VDI) \n\nproducts from VMware, Citrix, Microsoft and a range of smaller third-party vendors. VDI, though used almost generically to refer to other forms of desktop virtualization, means specifically to run a desktop operating system and all of \n\na users applications on a backend server without allowing other users to share the software or running much, if any, of it on the users own hardware. \n\nBMW Takes a Sharp Turn Toward App VirtualizationOther models stream applications or the operating system from a server to the user's machine and execute there, stream applications in the same \n\nway, or let many users share the same set of OS and applications. Those approaches make up, by far, the largest part of the market, according to research from International Data Corp., which predicts only 10 \n\npercent of enterprise desktop clients deployed this year will be virtual ones of any form. VDI is also more expensive than other formats because of the high requirement for server and network resources. A November, 2008 Forrester \n\nResearch report estimated each VDI user would cost an organization $1,760 for the cost of thin client, server, storage costs and licenses for \n\nvirtualization software, desktop OS and applications. In April, Natalie Lambert, the Forrester analyst who wrote the report and now works for Citrix, estimated that cost had dropped by almost half \n\nbecause more powerful servers could support more users for a lower price tag than during 2008. That trend will continue, according to IDC analyst Ian Song, but the cost of VDI is still several multiples above streaming applications or streaming \n\nOS versions, making the cost prohibitive for most users even if there were no support, security or management complications. Streaming applications, OSes and traditional terminal-services-based applications have been around long enough that the costs and security have \n\nbeen bulletproofed. Not so VDI. "The main issues are in security; neither of the biggest products, Citrix or VMware \u2014 both of which we talked with and tested these criteria \n\nwith \u2014 have a good semblance of role-based access control or scalability of management don't allow for delegated administration," Wolf says. "Citrix especially has been talking recently about customers with tens of thousands of seats, even one sale that will eventually be 140,000 seats. \n\nWe're not saying you can't do that," Wolf says. "There are lots of big installations of shared-services versions. With VDI the management consoles top \n\nout at 5,000 users and you can only set two levels of access. So you'd have stacks of these consoles of 5,000 users each and everyone would have \n\nminimal access as a basic user or would be a super-admin. That just won't scale."Relief By Late Year?Both Citrix and VMware will have updates out by the end of the year that eliminate the 5,000-user limit on management consoles and will make \n\nsecurity and access control far more granular; that they haven't done so to this point shows that even their larger installations are for relatively small pools \n\nof users \u2014 2,000 to 5,000 for the most part, not tens of thousands, Wolf says. Of the two biggest vendors in the comparison, compared, Citrix' XenDesktop 4.0 Platinum came closest to meeting Burton's criteria \u2014 \n\nwhich included the quality of user experience, network, storage and back-end virtual infrastructures, management, security, licensing and other issues. Still, the best it could do was qualify as being "suitable for department-level deployments and SME-class organizations."That's probably the best way to look at VDI anyway, as compared to other ways to deliver IT resources to a desktop virtually, according to Tony \n\nLux, purveyor of technology at Kansas City based regional craft brewer Boulevard Brewing Co., which used Pano Logic virtual desktops to automate its brewhouse.It didn't virtualize the desktops of its office workers, however. "The good thing about virtualizing with something like [zero-client specialist] Pano Logic is that on the brewfloor the computers are generally running \n\none app at a time and it works great," Lux says. "We put one office user on it and took him back off pretty quickly. He told us after the fact that he \n\nneeded to be more mobile and we couldn't support that, or use Windows 7 if we wanted to."Highlights from Burton Group's Head-to-Head comparison\n\nCitrix XenDesktop 4.0 Platinum\nJudgment: "Suitable for departmental-level deployments and for SME-class organizations."\nStrengths:\nFlexible delivery\nSupports multiple virtualization servers\nStrong user-experience feature set\nDiverse endpoint OS support\nStrong WAN performance\nRich supporting ecosystem\n\nWeaknesses:\nSecurity logging and auditing of administrative actions\n3 year support for entire product portfolio\n\nVMware View 4.01 Premier Edition\nJudgment: "Not...an enterprise-class SHVD platform"\nNote: "Upcoming VMware View 4.5 (in beta) release satisfies the required feature shortcomings."\n\t\nWeaknesses:\nRole-based access control or security hardening guidelines\nEnterprise management integration\nNo user application self service\nLow-bandwidth WAN support\nSupports only VMware backend\nManagement console scalability limited\nWin7 Guest OS support\n\t\nStrengths:\nRich integration with VMware vSphere\nSolid but incomplete core feature base\nPC-over-IP performance better than expected\nSimple deployment\nActive directory integration\nEnterprise management\n\nSOURCE: Chris Wolf, Burton Group\n\nFollow everything from CIO.com on Twitter @CIOonline.