vSphere 6.7 now supports 8 vCPUs and 128 GB RAM per VM.
vSphere 6.5 FT has more integration with DRS and enhanced Network (lower the network latency)
Fault Tolerance brings continuous availability protection for VMs with up to 4 vCPUs in Enterprise Plus and Standard is 2 vCPUs.
Uses a shadow secondary virtual machine to run in lock-step with primary virtual machine to provide zero downtime protection in case of host failure.