When the dust settled in the lab after two long months of testing Microsoft’s Hyper-V and VMware’s ESX in the areas of performance, compatibility, management and security, it all boiled down to two issues: experience and religion.

VMware ESX took home our award because in our performance and qualitative analysis of the hypervisor and the first tier of management tools offered by each vendors it showed depth and maturity while Microsoft’s Hyper-V’s components were both very Windows-focused and very rough.

Performance, as reported earlier this month, heavily favored VMware, although Hyper-V edged out ESX in a few contests.

On the compatibility front, Microsoft’s Hyper-V’s early lead in the number of supported hardware platforms (based on the widespread of support for Windows 2008 Server itself) is completely offset by a dearth of support for non-Windows virtual machine (VM) operating systems. While VMware’s supported hardware list is shorter, its support of a comparatively vast number of operating systems made us cheer.

VMware’s Virtual Center management platform is also mature and straightforward in how an administrator can use it to control resident VMs on a VMware host. VMware’s Virtual Infrastructure Client (VIC) is the administrative user interface to the VMware Virtual Center platform.

Microsoft’s System Center-Virtual Machine Manager (SC-VMM) 2008 (we tested a very late beta version which Microsoft guaranteed was feature complete) works with very strong ties to the underlying Active Directory and has an interface that fits right into Microsoft’s System Center scheme, so administrators won’t have to work hard to understand how it works. That said, things from standard management tasks such as viewing simple settings for a VM host to much touted advances features like the ability to migrate ESX VMs to Hyper-V caused SC-VMM to crash repeatedly during testing.

In terms of the security options for these hypervisor environments, we found that both vendors need to beef up their authentication protection schemes and provide a designated, secure store for VM images.

You can certainly dress up either of these virtualization platforms with a plethora of add-ins that cover everything from eye-catching GUIs to fast tracking for priority applications to special interest pork for favored hardware platforms. And these options could effectively be combined to be all things to all people, but we had to select the components we tested to get an even comparison.

Our line in the sand here was to select the basic bundle – comprising both the hypervisor itself and the management tools needed to build, execute, monitor and maintain a production virtual machine infrastructure.

Our test combinations were Microsoft’s Hyper-V using SC-VMM 2008 vs. VMware’s ESX Infrastructure Foundation package. We added only one option to the VMware foundation, VirtualCenter for ESX, which like SC-VMM is a starter kit for managing multiple virtualized host platforms. These additional software elements make the two hypervisor platforms equivalent.

Although we only very rarely test non-production software, we chose to use SC-VMM beta (Build 0991.1) in Hyper-V testing as it is close to public release and Microsoft contended it was feature complete and on target to be ready for a September release. That said, Microsoft has since missed that release target date and is now saying it won't even RTM the end of October. We'll likely take another look at the shipping code and compare it with what we found in this initial round of testing. What we found was that SC-VMM crashed frequently, hard and required a lot of configuration limitations that aren’t supposed to be in the final production product.