Been using Hyper-V since Server 2008 when it was originally released. The product has matured quite nicely. For full disclosure, I do NOT use System Center Virtual Machine Manager. I did have it stood up a few years ago to run some P2V operations. My experience was different from yours...the source machine was most definitely left intact.
We currently have two Hyper-V clusters using iSCSI-based storage. I'm about to stand up a third based on Server 2016, and will be redoing the original two clusters as a single four-node cluster, also on Server 2016. With the release of Server 2016 you can now run mixed-mode clusters and upgrade all of your hosts using the same hardware without having to purchase new, and without having to build a new cluster and migrate VM's over. You can do what's called a "shared-nothing migration" to move a VM from one host to another in real time. Server 2016 also finally introduces the ability to hot add memory to a VM.
From a cost standpoint, I just couldn't justify spending the money on the VMware products. I think most of you know that I work in higher education. Our Microsoft discounts are just crazy. The VMware licensing would have cost me more than my entire Microsoft agreement...for Servers, System Center, SQL, Windows and Office on all desktops, etc.
And don't get me wrong, vSphere is a great product. But Hyper-V fit our needs just fine and did it more cost effectively for us.
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