Just got through doin' a little experiment, boil two cups of water using my alcohol set up and my gas set up.
Gas set up: MSR Whisperlite International, Evernew titanium 1.3l pot w/lid - 2 min 30 sec to full boil, 14 grams of fuel
Alcohol set up: Super Venom stove w/windscreen, reflector, Evernew .9 titanium mug w/lid - 7 min to full boil 22 grams of fuel
My gas rig weighs about 390 grams more than my alcohol rig. I figure I cook about 3 times a day.
For this setup the break even point is about 16 days, the point where the alcohol rig plus fue is equal to the weight of the gas rig plus fuel.
I sure like the way my Whisperlite cooks, fast, no futzin' with windscreens but it looks like the weight penalty (about 12 ounces/340 grams) is too much.