It'd be interesting to see how meths compares to the above. I've always favoured my trangia stove owing to it's simplicity and reliability. Have also tried hexi/esbit (is there a difference between hexi/esbit tabs?) and have struggled to get a boil from one tab on half a pint of water. It's quite possible that this issue is down to the operator not doing enough to deflect the wind!
I have never 'used' meths so cannot comment, but I'll do some research on its Btu's etc.
I have the same issues with Hexy - 1/2 pint is 280ml and one tablet does not seem to get that to a boil, so it looks like, to get comparable figures it would take 4 hexy tabs to boil 1 litre (as per the gas test). It maybe that a percentage of the heat of one hexy tab is used to heat the pan, with the balance heating the water (I know that it all goes to heat the pan which then heats the water, but hopefully you know what I mean), once the pan is hot then subsequent tabs would pretty much be 100% heating the water, so maybe 3 tabs would boil 1 litre ?#
Hmmm - not explaining it very well am I !!