When to use ReFS in Windows Server 2016

Storage Spaces Direct - The new Windows Server 2016 ability for nodes in a cluster to share their direct-attached storage to form an aggregated, cluster-usable highly resiliency storage fabric aimed primarily at Hyper-V workloads. ReFS provides not only enhanced performance but a mixed resiliency type of virtual disk providing high performance and capacity

Hyper-V workloads - Because of the performance optimizations related to VHD and VHDX on ReFS any Hyper-V deployment on ReFS will benefit even outside of Storage Spaces Direct however Microsoft so far have very much focused on ReFS with Storage Spaces Direct so other Hyper-V scenarios have not received much focus yet. It should be remembered that ReFS does not support deduplication and so if that is a requirement (especially VDI) then you should stick with NTFS

Archival data - Because of the resiliency benefits of ReFS it is a good choice for data that needs to be retained for a long time. Remember that ReFS has higher resiliency when using Storage Spaces because it can interact with Storage Spaces to find copies of data when it finds a corruption