Despite stellar performance and its prominence as an "in-box" solution, Hyper-V still suffers from a couple of shortfalls. Among them:
• There is no USB support on guest operating systems. While that's fine for a lot of server-style deployments, client operating systems and other applications sometimes depend on USB utilities for usability and licensing. Solutions from VMware-Microsoft's most direct competitor --currently have this. There is currently a workaround, however, for common USB-based devices like smart cards and storage products: you can easily share these types of products with a VM through the Remote Desktop Client. Within MSTSC-this is the shorthand name for the Remote Desktop Client-navigate to the "Local Resources" tab, and under the "Local devices and resources" section, click "More" and select any device you like.
• The VMware VMotion live migration component, where administrators have the ability to completely move virtual machines and their associated storage and networking components to another physical host with no downtime, has no parallel on the Hyper-V side. This means there is still some end-user impact when a machine hosting Hyper-V goes down. If uptime is absolutely, non-negotiably mission critical, Hyper-V isn't yet there. And it's unclear at this point if and when this feature might be added to Hyper-V.
• You cannot add resources on the fly, a feature known as hot-add.
Hyper-V won't kill VMware or any other competitor right out of the gate. In my opinion, it's not yet ready for the "five-nines" deployment yet because of the lack of zero-downtime migration and no ability to hot-add resources.
However, on balance, it's a fantastic solution where the price is right, and for modest to important business needs, it is an excellent fit because of its solid performance and ease of deployment.