Every location will be different due to building configuration, fuel availability etc etc etc.
In the southern coal region in NEPA rental units are being converted from oil to electric baseboard. Propane is way too expensive to even be considered. Property around here is dirt cheap, buyers market, buyers buffet, buyers you name it. Flippers are buying as many houses and buildings as they can get at the sheriff sales and tax sales, ripping out the oil boilers, tanks, piping and radiators upgrading service panels to 200 amp and installing baseboard electric and bingo bango they are rented out in a couple of weeks. They then make the tenant responsible for electric taking the landlord right out of the heating supply business.
In a lot of the cases they leave the boiler and tank in the basement, sell any remaining oil in the tanks, sawzall the steam/hot water heating piping at just below the floor level, scrap the radiators for cast iron and away you go. Electric is expensive here but if I ain't supplying heat, what do I care, is their attitude.
Nat Gas right now is giving coal a run for it's money where Nat Gas is available in NEPA. I recently had to choose a heating system for our church building we rent. It was between coal and nat gas for heating. A hot water oil boiler was there but no piping and no radiators. Someone broke in long before we got there and cleaned it all out. At $3.45 a gallon oil took itself out of the running. Coal was my next choice but I couldn't get people to commit to 100% without fail that they would fill it with coal and take out the ash. A cheap abundant heating fuel doesn't do you any good unless someone is going to put it in!!!
The gas company said they would run a line to the building for FREE if we heated with nat gas. A donor gave us a 100K BTU two stage hot air scorcher for free. Gas line installed to building for free, air scorcher for free.....easy decision to make. Total spent to install heat for our church, $742. Volunteers ran the gas lines from the meter to the furnace and a small free standing 20K BTU unit for that little extra when you don't need the big unit to run. We installed the flexible ducting and floor vents. This was a no brainer. Kinda ironic when here we are sitting in the southern anthracite coal fields 15 minutes in any direction to four coal yards and decided to go with nat gas. I would say go figure but that's exactly what we did and long term, nat gas won.
Our landlord loves us since it cost him nothing and he now owns a heated building. We got a good break on the rent because no heat was the least of the issues this building had when we moved in.
It all boils down to dollars and cents on operating costs and maybe more so when you factor in how often are you going to have to look at the unit.. Some areas have copious amounts of nat gas, some oil, some propane, some coal, some wood. What's it gonna cost YOU to stay warm during the winter.
Count the cost of everything, not just the equipment and for sure not just the fuel. Count the cost is not just a biblical admonition for ministry. It covers everything we do in life. Just don't go into analysis paralysis while your counting the costs.