NSX-V has been around for a while and has powered a lot of software defined and cloud environments. If you are VMware cloud provider and are still using NSX-V, you should make the switch and this is why.
First, an intro for those who are not familiar with VMware NSX, NSX is VMware’s Network Virtualization solution. It allows you to build software-defined networks in virtualized datacenters that are abstracted or separate from the physical networks. This means that you can create virtual networks including switches, ports, routers, and firewalls all in software having it run over your physical network devices, any physical network device.
VMware NSX comes in two flavors, NSX-V and NSX-T. NSX-V is typically called NSX for “vSphere” and is the first version that has been around for years. It was designed for on-premise VMware vSphere deployments such that a single NSX-V manager is associated with or tied to a single vCenter Server instance.
NSX-T is the second type of platform and is typically called NSX “Transformers”. 
(yea, cool name). It was released and designed to address the deployment models that NSX-V could not fix and features an agile software-defined platform for building cloud-native application environments. Unlike its predecessor, NSX-T is built to handle multi-hypervisors, cloud, containers, and bare metal server environments and incorporates agents to perform microsegmentation on non-VMware platforms.
As shown in the figure above, the NSX-T architecture is designed around four fundamental attributes that span from any site, to any cloud, and to any endpoint device. This enables greater decoupling, not just at the infrastructure level (e.g., hardware, hypervisor), but also at the public cloud (e.g., AWS, Azure) and container level (e.g., K8, Pivotal); all while maintaining the four key attributes of platform implemented across the domains.
For VMware Cloud Providers, VMware has released a migration tool – VMware NSX Migration for VMware Cloud Director 1.2.1. This tool helps providers running a VMware Cloud Director environment to migrate NSX Data Center for vSphere (NSX-V) to NSX-T Data Center. The tool is an external automation tool that initiates and completes the migration process with minimum downtime.
Check out this VMware blog for more features of this tool and the considerations you need to make before proceeding. It was written by Romain Decker, a Staff Technical Product Manager within the Cloud Services Business Unit (CSBU) at VMware.
In addition, there’s an older 24-page white paper also by VMware that details several ways to migrate from NSX-V to NSX-T. The white paper looks at various approaches available for migration and also focuses on Migration Coordinator, a tool built into NSX-T that simplifies in-place upgrade of NSX-V based infrastructure to NSX-T.
Just My Musings 