KVM is so-called full virtualization mechanism, which means that it is as close to the real hardware (dedicated) server as possible.

For example:

• it's possible to install multiple different OSes
• each VPS has own copy of the OS including own kernel
• you may freely modify OS settings including loading any kernel modules or installing custom kernel
• offers full emulation of NIC, which enables unrestricted access to network stack (full iptables), and ability to run any advanced network related software such as VPN tunnels.
• enable you to use fully graphical VNC console, exposed in the Client Area as HTML5 based noVNC
• allows running software tightly integrated with the OS kernel such as Docker

KVM is also more secure than other solutions (like OpenVZ) as it provides better separation (own kernel), and ability to use block level encryption.