Windows VPS is the newest in the world of hosting services. It has been creating quite a stir ever since it has been introduced. There are 3 most popular technology to virtualize a windows based server.
1. Hyper-V - Powerful technology by Microsoft.
2. Virtuzoo - A Unique product of Parallels.
3. VMWare - Hardware based virtualization techniques.
Hyper-V being Microsoft's product is the most economical & powerful in it's segment. It tightly partition your virtual servers from each other. It partitions each windows vps in such a manner that cannot allow them to share each other's freely available RAM.
Being a Microsoft's product it has management features (start, stop, shutdown, installation, management, etc..) that tightly integrate with windows based servers.