Now that Hyper-V is RTM, why should you care? Because it performs very well! If you do demos using virtual machines on a laptop, do yourself a favor and upgrade to Hyper-V. If you have a production data center with lots of virtual machines, you might want to wait until System Center Virtual Machine Manager (SCVMM) is available. Management of virtual assets is critical in a production environment. SCVMM 2007 does not manage Hyper-V machines.
If you are currently running virtual machines using Virtual PC or Virtual Server, you'll want to preserve your existing virtual hard drive (vhd) assets. You can do this manually be following these steps:
1. Make a copy of your vhd.
2. Run the vhd in Virtual PC or Virtual Server.
3. If Hyper-V requires a higher service pack, apply it now.
4. Remove the Virtual Machine Additions.
5. Save and permanently commit the changes.
6. Make the updated vhd available to Hyper-V (e.g., copy the vhd to the Hyper-V physical machine, put it on your SAN, etc.)
7. Create a new Hyper-V virtual machine using the updated vhd.
8. Install the Integration Services into the virtual machine.
Must you apply a service pack while you are still in the Virtual PC or Virtual Server environment? It depends. There have been times I've seen the mouse unavailable in Hyper-V until Integration Services was installed. But Integration Services can't be installed until the machine is at the correct service pack level. Since Integration Services makes the mouse available but requires the service pack, you can be stuck installing a service pack without a mouse. It's a Catch-22. Avoid the trouble, install the service pack before moving to Hyper-V.
With RTM, more operating systems and service packs are supported. XP service pack 2 is now supported. If you want to run XP using two virtual processors instead of one, you'll still need to upgrade to service pack 3. Windows 2000 with service pack 4 is now supported, which is great for those legacy machines running older versions of SQL Server.
I'm running the RTM version of Hyper-V on my dual core laptop. Performance is excellent. My laptop is set to single boot into Windows 2008 Enterprise x64. It has the desktop experience, Aero, and audio enabled. The only feature it doesn't have that I miss is Windows Media Center.
See John Howard's blog for version number information. http://blogs.technet.com/jhoward/archive/2008/06/26/hyper-v-rtm-announcement-available-today-from-the-microsoft-download-centre.aspx