Last week I started our migration from VMWare’s VI3 to vSphere. There are many improvements to the load balancing capabilities as well as the management capabilities. The storage engine has been greatly improved as well. Storage vMotion is available in the GUI without a plugin and thin provisioning is finally available, which is a huge boon and reason enough to make the move on its own. Most of this process can be completed with no downtime for the virtual machines.