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It's likely that shops with both windows and linux will use vmware if they need it's features, or xen because it's free. I don't really see a place for Hyper-V anywhere that's not totally locked in to microsoft... It's not tried and tested like the other products, it has a large footprint and will cost more than xen.
Not even sure if it offers much above vmware's free products either.
The only places that will use it, are those who are locked to 100% microsoft and cant/wont touch anything else.