Well this is the “billion dollar question”, now isn’t it? As Microsoft has a reputation for taking over companies and integrating or renaming those companies’ products into their own, it is easy to speculate that Microsoft’s Hyper-V will overtake VMware’s ESX Server in the virtualization top spot.
However, VMware has, in my opinion, at least a 2-3 year technological lead in the number of features that it offers and its general development. More importantly, VMware has developed a huge enterprise, and more recently, a strong SMB customer base. VMware has 10 years of virtualization experience, every Fortune 500 company uses its products, 92% of the Fortune 1000 use ESX, VMware as 11 virtualization patents, and over 100,000 customers worldwide.
On the other hand, as of this month, Microsoft just released their first enterprise virtualization product (Hyper-V) and that product is missing many of the features that it was originally advertised to have. While those features may come in the next version, even with those features, they will still be far behind VMware in the functionality of their Enterprise virtualization product and their customer base.