I think you are tallking about what we here in the States call "sterno". It does not make as efficient a stove as the mini-alcohol types. For example, it takes 15 minutes to bring 8 oz. of cold water to a boil over sterno. But I use it while hunting/hiking because it is so simple to use: just pop the lid and light. No measuring fuel or packing a seperate fuel container. I fabricated an aluminum ring about 1" high that fits around the top of the can that allows me to heat cans or water on it. I usually get 2 1/2-3 hours per large can.
Like I said, it's not going to win any speed contests, but if you are looking for a safe, simple, and convenient means of heating food or warming yourself on the trail then sterno is hard to beat. For my vehicle or home I would probably go with a white-gas or propane stove for cooking (NOT heating.)
I like sterno so much I bought a case on Ebay not too long ago.

(Drinking it is not recommended! <img src="/images/graemlins/smile.gif" alt="" />)

Regards, Vince