But I think the biggest issue in New England (and California) will probably
  be the high cost of electricity. In most of the country, heat pumps are a
  huge no-brainer.

PG&E charges about $2.44/therm (100,000 BTU) here. So yea that's well cheaper than electricity – I think it works out to about half to a third the cost of resistive electric heat. So (for now) a heat pump that's about twice as efficient as a gas furnace would work out to about the same cost. Unless you do something like a mini split where you're heating a smaller area.

The big thing to keep in mind is that California natural gas prices spiked for a bit last year. All of a sudden gas heat was very, very expensive.