NAG, We're looking to build a high availability virtualization system, with a focus on VMware vSphere and Microsoft Hyper-V. While Microsoft has a clear price advantage (a mere fraction of the cost of VMware's offering), I'm not convinced that the two products are in the same league. Both solutions tout scalability, but I have my doubts in terms of management, performance tuning, overall robustness, and even ease of implementation. I'm interested in your experiences with either or both of these products, preferably in their latest iterations and in a HA architecture. Input based on similar assessments is particularly invaluable. Thanks, Tony