The old XP mode used the antique product Virtual PC, which wasn't bad in its day for a program running on top of Windows that emulates another PC. Client Hyper-V is a real hypervisor with Linux drivers for its virtual peripherals that run far better than forcing Linux to run on the primitive virtual machine presented by the old Virtual PC. I'd like to see Linux enthusiasts demonstrate how well it runs on Client Hyper-V, which might entice Windows users to give Linux a serious look.