This would obviously depend on the honest efficiency of the particular appliances in question......
it is the nature of "sales" to try to put things in the best possible light for a profit, but the real equation would have to take into account.
1. Cost and longevity of the appliance.
2. Efficiency of the appliance
3. Work required to keep the baby going
4. Yearly costs in maintaining and parts as the years go by.
5. etc.....
Let me give a rough example. I buy a top of the line pellet stove installed for $5K.
Realistically, it lasts me 12 years if I am lucky without very major repairs (this seems average, some go sooner, some go later)
I burn 5 tons of fuel a year.
That's 60 tons of fuel.
It costs me $100 a year for the first 5 years to have it cleaned and maintained, and then $200 a year from year 6-12 (inflation, more parts, etc.)
OK, so total cost to burn that 60 tons is about 7K in addition to the pellets. Divide the 60 tons into 7K, and there are over 100 per ton of extra costs in the pellets......beside the work involved.
This is just one example. Obviously, if you have a $1,000 pellet stove you installed yourself and you do all the repairs, it may end up being only $40-50 a ton in extra costs.
As with all such things, it depends........
Pellet stoves have still not yet shown themselves to be anywhere near the reliability of oil and gas furnaces....my guess would be they are not even in the same ballpark. That is a major sticking point....along with future service and parts availability. I like the idea of the independents starting to work on pellet stoves (like Pelletstoveservice.com, etc.) because that solves one part of the equation.
Also, pellets have gone up 20% in recent weeks...right along with oil. There is very little reason for this, but pellets have always tracked closely to the price of oil....that is, went up when oil went up...sometimes dramatically.
Here is our fuel cost calculator - the default efficiencies should work fine, but you have to change the prices......
https://www.hearth.com/econtent/index.php/articles/fuel_cost_comparison_calculator/