WordPress MultiSite allows you to manage one to many WordPress sites and blogs from one interface. WordPress MultiSite provides a central location for upgrading WordPress, WordPress Themes, and WordPress Plugins. Other benefits including saving database and site disk space.
Parallels H-Sphere (sometimes referenced as HSphere) allows hosting providers to automate the infrastructure across multiple servers. In someways H-Sphere is like WordPress multisite in that you have one H-Sphere installation managing multiple servers from a central location vs. other automation systems which require a complete install of their software on each server with each server managed separately.