In Windows 7 Professional, I used Windows XP Mode that Microsoft had available to allow you to run older programs in Windows XP that would not run in Windows 7. Microsoft's obsoleted Virtual PC and did not make Windows XP Mode available for Windows 8. The new method of running Windows XP is through a virtual session. Using virtualization in the desktop environment is nothing new to me. I previous used VMware Workstation for years to run other Windows versions for support reasons. The same applies here, but there are some differences now.
Microsoft's Hyper-V does not support USB devices and there are other limitations that has been discussed in various news articles and blogs. To run a guest operating system in a virtualized session, you cannot run the guest OS at the host OS screen size resolution. For instance, on a laptop the guest OS will not adapt to the host OS video settings. This feature is important to me as it affects how I work with and use the guest OS. Hyper-V also seem to greatly slow down the computer when the guest OS ran. I'm using a laptop with Windows 8 Pro x64, 8GB DDR-3 memory, and 750GB SATA hard drive. I also have to uninstall and reinstall Hyper-V at times in Windows 8 whenever Hyper-V would stop running for no apparent reason.
I downloaded and installed Oracle's VirtualBox, free virtualization software, to run Windows XP Professional and Windows 7 Professional. The two main features that Hyper-V lacks, USB device detection and guest OS using host OS screen resolution, are available in VirtualBox in the guest OSes. VirtualBox guest OSes seems to run faster on the same system where Hyper-V did not run them as fast and efficient. The guest OSes in VirtualBox, based on what I am seeing on my system (as the results may vary per system and configuration) run fast for a virtualized operating system.
Since I do run Linux Mint 14.1 on a second laptop, I can install Oracle's VirtualBox in Linux and copy over the installed guest OS(es). This saves time on re-installing, re-setting up, and re-updating all the guest OSes between the two host OSes. This also provides a back up of the VirtualBox guest OSes in case I need to ever get them back, and also a way to always keep them up-to-date. If one guest OSes gets updated on on one of the two host OSes, I can just copy the VirtualBox files between systems. So far this method is working. I do not know of any problems that may occur to break this backup method to keep the guest OSes running on both host OSes.
Based on my results between Microsoft's Hyper-V (built-in to Windows 8) and Oracle's VirtualBox, I may continue to use VirtualBox to keep the guest OSes running on both systems. Especially when Hyper-V is not available in Linux.