NFS 4.1 brought a lot new features comparing to its predecessor NFS 3: Multipath, “reliable” transmission based on TCP, and better authentication support. And ESXi comes with native support for NFS 4.1. But what if I tell you that, under a very specific circumstance, NFS 4.1 will result in all your VMs being forcefully powered off, and causing data loss?
TL; DR: Avoid NFS 4.1, stick with NFS 3 on your vSphere cluster, especially if your storage backend have relatively poor performance.