A. There are no exact performance measurements to confirm or deny this, but from what I've seen and researched, performance isn't a factor in choosing the hypervisor layer. On the same hardware and same virtual configurations (use of virtual disks, etc.) both systems would perform pretty much the same, with negligible difference. The decision on which virtualization platform to use is more likely to be based on advanced features such as high availability, guest support, management tools, and hardware support.
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