What is the difference?

dfranc

Out of curiosity, what is the difference between Hyper V Manager and V-sphere and also ESXi.

Essendon

Hyper-V Manager is a console local to every Hyper-V host using which you can manage VMs on it, use the console to connect to other Hyper-V hosts and manage their VMs too. Hyper-V Manager only has a limited set of available things you can do with it, the good stuff comes with SCVMM.

vSphere is VMware's flagship suite of products. It includes things like ESXi, vCenter etc

ESXi is VMware's hypervisor (on which you create VMs). Hyper-V is Microsoft's hypervisor. Both are type 1 hypervisors because they go directly on the host's hardware.