Er, essentially the same people that would use Virtual PC, albeit a much more limited audience?
Anyone testing multiplatform compatibility (let's say I'm a Windows web page developer that wants to see how a page looks on Safari), people who have to run Mac-only programs and have no access to a Mac, people who want to take advantage of multiple virtual machines (I regularly use Virtual PC or VMWare when I'm using a Mac *OR* a PC for its ability to let me run multiple test copies of OSes, etc at a time, it's VERY useful for doing testing), hobbyists, multi-platform application developers, etc.
The fact is that CherryOS is vaporware (it's a non-existant product, end-of-story), however, and PearPC is nearly unusably slow (it'd be better if Apple offered a cheap $500 PC to these same people, but that'll never happen)