IP addressing can be a problem for administrators when moving VMs around, especially from facility to facility, as each is likely to have their own location-endemic addressing allocation needs.
The prior version of vSphere, while allowing for a bit of location-diverse addressing, didn't have strong multi-site transparency. The new virtual switch takes care of a lot of the misery for both IPv4 and IPv6 addressing schemes. It's not quite ideal, and some administrative functions must be done outside of the appliance, but its visuals allow a more inter-site understanding of addressing needs and allocations.
We used both our lab and our NOC resources to launch varying sized VMs of different operating system types — mostly Windows 2003/2008 R2 and Red Hat, CentOS, and Ubuntu Linux. There was no mystery. VM conversions were unmentionably easy, save for some important characteristics: we now had up to 32vCPUs per virtual machine (with advanced licensing option cost), and could see a tremendous amount of oversubscribed (if set) memory and storage. (See how we conducted our test.)
It's possible to thin-provision (oversubscribe, under-allocate in actuality) almost every operational characteristic of a VM. Doing so has benefits, depending on the settings we used, and allows vSphere to make recommendations, or simply move VMs from one server to another to manage actual needs, vs. initial judgments.
In doing so, VMware has also met a checklist item with over-subscription capabilities for those needing multi-tenancy options, as thin-provisioning permits "elbow room" that can be later physically provisioned when tasks and campaigns mount up.
In other words, less needs to be known about actual server behavior, as VMware can be set to move VMs around to match their execution needs, even when those needs have been capped/throttled by an administrator. Using set guidelines, vSphere will refit VMs into servers to adjust workloads and demands. Control over what VMs go where can be very highly defined and rigid, but ability to fit VMs into hardware servers based on their performance characteristics takes a little time as it's based on accumulated observations of behavior.
It took nearly a day before vSphere started to move things around, although we could have made it more sensitive (and move more quickly to adjust), but we wanted to see what it would do.