VMware ESX Server offers a datacenter-class virtual infrastructure designed for mission-critical environments, providing substantial cost reductions (40% in hardware/software costs and 70% in operational costs) and enhanced reliability. The technology utilizes a thin virtualization layer that allows multiple operating systems and applications to run efficiently on shared hardware, improving resource utilization and business continuity. Key features include granular resource management, support for various guest operating systems, and advanced capabilities like VMotion for dynamic resource allocation.