This is a comprehensive comparison of the leading products of the Software-Defined Storage market, featuring Microsoft Storage Spaces Direct, VMware Virtual SAN and StarWind Virtual SAN. It provides numerous use cases, based on different deployment scales and architectures, because the mentioned products all have different aims. As the market is already large enough, the vendors used to dwell its different parts, but lately they entered a full-scale competition, adapting their products to meet general demand. This post is an analysis of how Microsoft, VMware and StarWind fare in in the Software-Defined Storage market right now. The approach is practical and all the statements are based on the experience of virtualization administrators and engineers from all over the world.