Microsoft issued another release of their hypervisor today, ahead of schedule for the second time. The official launch for the suite is still scheduled for the end of February, and it is Microsoft's intention to get more feedback on the software as-is. They have an obvious incentive to make it available as soon and as often as possible, as it will be difficult for them to gain ground over their biggest competitor, VMWare.
One bone of contention they have faced several times in the past over their hypervisor (and virtualization in general) has been their licensing policies, which they have begun modifying after the initial beta was poorly received. A friendlier licensing will sure help them, even on the OS side, no matter what virtualization suite a company chooses.