It supports only one virtual machine at a time, while VMware's Fusion and Parallels support more (Fusion can run 20 virtual machines concurrently).

FORBES: Magazine Article

"Many customers suggested they were unlikely to switch from VMware to Hyper-V at any price, since Hyper-V lacked virtual machine mobility as well as other higher-level features such as disaster recovery, " Rueppel wrote in an April 1 research note.

FORBES: VMware's Future Challenge

SanDisk announced that it is offering VMware server cache that can accelerate application 3-5 times and increase the number of supported virtual machine by 2-4 times.

FORBES: Flash and Fire -- Flash Memory Announcements Before FMS 2012