Can't speak to anywhere else but where I live. Two years ago I went through the process of quoting out a ground-source heat pump. Total out of pocket cost for Installation was around $40k. Payback took about 16 years, using whole year savings estimated (heating and A/C both). The warranty on the unit was only 10 years, and as mentioned above my neighbors got hit with a $16k repair bill when their unit failed right around the payback point (which extended payback out another 6+ years for them).
I love the efficiency gains these units bring. But until they make financial sense, adoption is going to have to be driven by other, far less effective motivators.