When I first started covering virtualization a couple of years ago, I saw a lot effort being put into selling virtualization itself. There were, apparently, plenty of people who needed to know that virtualization could save companies time and money and help them use their resources more efficiently.
At VMworld this year, I heard several different people talk about increasing the percentage of any given company's IT infrastructure that's virtualized. I didn't hear anyone trying to convince listeners that virtualization was worthwhile in the first place. Obviously the audience for VMworld is less likely than most of the world to need that kind of convincing, but the trends I noticed at that show are also what I'm seeing everywhere else—IT Pros seem to believe that virtualization is a good thing, and they just want to know how to do it well.
I see a similar trend in virtualization products themselves. With Windows Server 2008 R2 SP1, Microsoft has addressed the last big technical gap between Hyper-V and VMware's offerings. There are still technical and financial differences between the various hypervisors, but there's nothing so big that you'd be shocked to hear that a company chose one over the other.
Virtual desktops seem to be going the same way. Last week Citrix announced new versions of XenDesktop and XenServer and upgrades to the Citrix OpenCloud platform. Check out the features listed in the XenDesktop press release, for example. Citrix is working on making VDI that are faster, smarter, and more versatile, but they're not adding new, giant features. My guess is that there aren't really any giant features left to add, just evolutionary improvements.
To me, all these trends say that virtualization is a mature technology. The companies selling virtualization still have to convince you that VDI will work in your environment, or that you should have 80 percent of your servers virtualized instead of 40 percent, or that the management features in their products make them better than the less expensive products from their rival. But for now the playing field is pretty level, and there's no killer feature that one company has and the others don't.