Exporting a Virtual Machine is a great way to keep it as backup, move your Virtual Machine in another HYPER-V Server or Client HYPER-V OR archive a Virtual Machine that you want to deleted from your HYPER-V. It's a simple process and you don't need any third part tool.
Client HYPER-V is the virtualization technology that was introduced in Windows 8.1 and it's built upon the same virtualization technology that is available in Windows Server.
Virtual PC's are very helpfull for advance users or for IT to do different tests or configurations. As IT my Laptop it's very important and i can't imagine if need to format from the beginning because of a problem in the middle of a day.