What is NFV? These are virtualised Carrier/SP services that have historically run on dedicated, proprietary hardware in the field. A great example is an LTE Base-station controller or an MPLS Provider Edge router, where rather than buying the dedicated hardware appliance from the vendor, you buy the licence for the Virtual Appliance (NFV certified for use with vSphere) and deploy it in a vSphere cluster instead; which is much more efficient when you combine multiple NFV services in the same vSphere cluster.
You may have read my recent Next-Generation Data Center post, that summarised the Conceptual Model and Logical Design of my ideal Private Cloud solution. This post describes the current vendors that are the leaders of their respective markets and I believe they have a compelling integration story with the highest chance of success. The back-bone of the strategy relies upon VMware, who in my opinion are the current leaders of SDDC for technology, professional services, training and support.