1:40 p.m. on April 2, 2011 (EDT)
allie asked -
And Bill (or anyone), what's the advantage of having a canister you can tip upside-down (invert)?
as did denis -
I cant say anything about the stoves you have chosen but I am interested in Bills reply as well.
Seems like I have answered this question at least a dozen times in the past 6 months here on Trailspace.
Explorer Robby and Hikin Jim meanwhile are debating what kind of weather "most" people go out into. (hey folks, when it comes to weather, ya gets what ya gets - every time I ask my son, the atmospheric scientist, to arrange the weather to my liking for the trek I am about to embark upon, he says "I'm not that kind of an atmospheric scientist!")
allie,
The short answer to your question is at the end of this post.
The details are first - Brunton, MSR, Primus, Optimus, Trangia, Sigg, and Coleman (with its plethora of subsidiaries and brand names) all make good stoves, IF you follow the directions (yes, that means reading the directions that come with them) and do a little maintenance once in a while (that isn't directed to you personally, allie, but to a number of people who pop up here and on other sites to complain bitterly about their brand new stove that has utterly failed, deny what the very knowledgable and helpful people try to advise them, and blame everything on the manufacturer).
Anyway, at what you indicate is your stage of learning and near-term intended usage, canister stoves are the easiest to use. As for the choice between the two you mention, the Raptor is the smallest and lightest, but is a bit slower to boil. The Windpro is more stable, slightly faster to boil, and allows using a windshield that completely surrounds the burner area.
As has been mentioned, one disadvantage of the compressed gas (canister) stoves is the poor (or no) performance at low temperatures. Getting the canisters with a mixture of gases helps mitigate the problem (look for canisters that use isobutane plus propane with no butane by MSR and Markill - more expensive, but worth it for the cold problem). Speaking of expense, larger canisters are significantly cheaper per ounce of fuel than the small ones, though the tiny ones are more compact for short backpacks.
Of the various solutions for the cold problem - yes, some people sleep with their canisters. This is only effective for a short use of the stove. The problem is that the pressure to feed the gas to the stove comes from evaporating the fuel. This evaporation requires drawing heat from the fuel (hence cooling the remaining liquified fuel) and to some extent the environment. When the remaining liquified fuel drops below the vaporization temperature of each component of the mixture (32F/0C for butane, 10F/-12C for isobutane, -40F or C for propane), that component no longer contributes to the pressure. So at, say, 20F, butane is no longer evaporating, but the propane continues to vaporize and feed the stove. But since propane is only 20% of the mix for most brands, the stove quits after about 1/5 of the fuel is burned.
So sleeping with the canister will probably get you through breakfast - now what? You could set the canister in a shallow pan of water - as long as the water is liquid (hence above 32F), the canister can draw heat from the water and keep burning. Just don't use hot water! (you will get flaring from the stove). You could also use a hand warmer or toe warmer (the toe warmers are a good size to stick in the concave cavity in the bottom of the canister, plus usually have adhesive to keep it in place). Primus makes (or used to make - haven't seen them in a while) a "cold weather" kit, which was essentially one of the little handwarmers. Little Hotties is one brand. But the handwarmers do not work as well at altitude - they need oxygen to react with the charcoal in the handwarmer.
OR -- if you have a remote burner (as the Windpro does), you can invert the canister. In this case, as long as there is some propane still in the fuel mix, the stove will work down to -20 or -30 deg reasonably well (I have used my Primus MFS down to -20F this way). In this case, the vapor providing the pressure forces the liquified gas through the hose to the burner. If the stove has a generator tube that runs up next to the burner (as with the Windpro or my Primus MFS), the liquified gas is vaporized and gives smooth burning. This does work with remote burner stoves that lack the generator tube, if you are careful.
So the short answer to your question is - the advantage to a canister setup that can be inverted (not merely tipped on its side) is that you can operate the stove at much lower temperatures without resorting to liquid water or handwarmers.
An alternative answer is that liquid fuel stoves are more versatile in the long run and for more extended trips, particularly if you are traveling to Third World countries.