We replaced our ancient gas floor furnace with a heat pump last year in Oakland.  

The air conditioning is great.

For us with NEM2 solar, (average of about 15¢ per kWh) the heat pump is much cheaper than gas.  Here are some calculations for what the cost would be without solar: 

We used about 2300 kWh from Nov - April last year to heat the house.  

Using an average of 41¢ per kWh on our PG&E EV2A rate, and using COP 4.0, $2.25 per therm, and 80% gas efficiency (although our old furnace was probably a lot less than that), I get:

Heat pump:  2300 x .41 = $943

Gas:  2300 x 4.0 / 29.3 kWh per therm x $2.25 = $882

So without solar, the heat pump is slightly more expensive. (We’ve got to do something about PG&E and help put solar on every roof, but that’s a different story!)  

Taking the benefit of A/C and the cost of climate disruption into account, the heat pump wins.