I haven’t tried KVM yet as I’ve been too busy and Xen is more mature – but many of the accounts I’ve read seem to indicate that for Linux its performance is very good maybe better in some cases than Xen. Management is another issue, but that is just a matter of time and development enegry.

From lwn.

• Thread: Howto for migration from VMWare ESX
• Virtual Disk Migration Utility 1.1
• Converting a Physical Disk to a VMWare Virtual Disk
• Thread: VMware Linux guest to Xen
• VMWare to Xen Migration
• Thread: Migrate VM under VMWare Workstation 6 to XenServer
• Thread: v2xva failure in converting .vmdk files? – phantom disks in vmx can make v2xva fail.
• VMware KB #1308 – Cleaning Up After Incomplete Uninstallation on a Windows Host- removing Vmware Tools can be troublesome. Check this kb article and also note the following location in the registry.
• VMware server memory controller service failed to start

The vmmemctl.sys driver is missing from your system or the registry contains the wrong image path. The \??\ is normal in the path.

If you selected the default path for the VMware Tools, your registry imagepath should look like the example below.

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\VMMEMCTL]