You can measure an empty canister and a full one in water. If you mark it in both places, then you know about how much is left by simply setting it water anywhere, even while you are hiking. Hikin Jim did an article on this.
http://seattlebackpackersmagazine.com/how-much-gas-do-i-have-left/
As far as what you choose for hiking long distances, it depends.
How long between resupply? once every 4-5 days, 5-8 days, 8-14 days?
How far to hike to get to a post office or resupply? 2-4 hours, a day?
What kinds of fuels are available at the resupply? Small stores often don't have esbits, or kero. Often canisters can be difficult, too (you are not supposed to mail them. I think a pacel post service is OK.))
How do you cook? Boiling water only? Steam Baking, frying some foods, macaroni, etc?
What do you cook? FBC, or, Fetuccini Carobara with fried trout? Stew and potatoes?
How often do you cook? Once, twice or three times a day?
How much do you need for each meal? 2 cups per meal, or, 3cups of coffee and 2 cups of oatmeal?
What is your tolerance for cleaning soot? Wood, Esbit, and kero all produce some.
What is your tolerance for odors? Esbit smells bad. Wood smoke flavours water. A spilled drop of Kero will stink for a week.
How do you like to hike? I like light when I start, lower than that at the finish is of lesser importance. Alcohol is heaviest to start, pretty light to finish. WG is often lightest to start a longer hike, heaviest to finish.
There is no one answer that will satisfy every criteria. I like to bring a cone and alcohol stoves (set up for a modified grease pot) for solo hikes of 2-3 days. For a week to to 13 days, I bring my SVEA and 10oz(12floz bottle & fuel)of fuel. An Alcohol stove outfit for 13 days is too heavy with my usage.
I boil about 2L per day using about 3/4oz of fuel including priming with the SVEA.
I burn about 3oz per day of yellow HEET per day including priming.
I burn about 3 tabs of Esbit per day. (Edit: should be about 3oz per day)
Total weight: SVEA + fuel = 27oz (discounting the cup.)
Total weight: Stove/cone + Alcohol= 37oz
Total weight: Stove/windscreen + Cannister=~36oz (Gave these away 5-6 years ago.)
Total weight: Stove/cone + Esbit= ~34oz (quite sooty, I don't use it anymore.)
Finish weight for SVEA: about 18oz (stove & bottle)
Finish weight ofr Alcohol: about 6.5oz (cone, stove & bottle)
Finish weight for Canisters: about 17oz (stove & cans)
Finish weight for Esbit: about 6oz (cone, stove & wrappers)
So for roughly a two week trip, at my usage, I take WG. Canisters are not usually available within walking distance of the trail(read a full day of road hiking, usually.) Alcohol is "iffy", sometimes all I can find is isopropynol which doesn't burn that well, leaving soot on my pot…I don't use alcohol for longer trips so I should have removed it from the above list, anyway…too much "starting" weight. I don't use esbits: sooty and smelly. I don't use canisters, the weight of the can kills them except for single short trips (about 3 days) but I would bring alcohol for that short of a trip.
To me, this says they are about equivalent give or take. Therefor, I take what works for me. (This data is all approximate based on my real use. I have had one very light WG stove that went through about 4 times more fuel: The Simmerlite. This one is just plain terrible on fuel. The old Whisperlite isn't much better. Several others were not too bad, using about double or less the amount of fuel: XGK, Dragonfly. The most important determiner in fuel consumption is turning the stove down. If it cannot do a low simmer(~750BTU) steadily, it will burn LOTS of fuel.)
Edited for clarity…