Lots of variables here, but I have found that with my house: installing new units (originals were 18 years old, new ones look MUCH better too) and also upgrading the thermostats to Programmable Line Voltage (Honeywell makes a nice one, they are pricey thought, about $55each which in most cases is more than the heater!) really helps keep the cost down. Hard to tell how much of electric bill is heat vs. hot water or appliances, etc. I would say that the heating and hot water portion probably is about 15% more than the cost of what my neighbors with similar houses use in oil.
You can look at it a couple of ways - upgrading to oil is about $10k. I PROBABLY will see that when I sell the house, hard to tell. I mean *I* bought it with eletric heat knowing I might upgrade in the future - someone else probably would too, esp. in recent market. So don't let resale scare you away, that's just oil company hype.
With severe allergies and asthma the electric heat is nice and clean and QUIET.
You don't have to maintain a furnace or worry about the price of oil. These recent sad days in the world, I'm guessing the cost of oil is a major concern.