Understanding licencing is the key...
Most people that deploy Windows in a virtualised environment, whether VMware, Hyper-v, Xen or whatever, will use Microsoft ECI licencing model as it licenced per socket on the virtualisation host for unlimited instances. The thing with ECI is that it also includes all the rights to use the whole system center suite on those VMs. This is when it starts looking really attractive. Having spent the second half of last year reviewing private cloud solutions I am confident that the suite provides a comphrehensive platform at a fraction of the cost of it competitor. This is due to the fact that if you want equivilent functionality in the VMware world you need to buy vCentre, plus vCloud director, plus vOps manager etc and all of these ancillary products are licenced per vM - this gets far more expensive as you scale. As Mcirosoft licence per socket you are rewarded with better economies of scale.
If the Microsoft solution is 'good enough' which for most IT shops I suggest it will be, then why pay many multiples more or something broadly equivilent? Start looking at Windows 8 Server Hyper-v and microsoft look to take a clear lead on the functionality front too. I have no beef with VMware, we currently deploy it and hosts hundreds of VMs on it. However the cost is prohibitative and in the current climate I'd rather move to Microsoft that invest further in VMware for a product where the value aspect is diminishing.
