Jess and are huge proponents of simplicity. The simpler something is, the less ways it can break and the more likely it is we can fix it. So, we've always preferred alcohol stoves for everything but the coldest weather, where the BTU/sec of alcohol is frustratingly slow for melting snow.
In the interest of trying to carry less, particularly less consumables, and detaching ourselves from the bonds to society consumables bring; we've done a lot more cooking on simple open fires lately. It turns out it's really quite easy, though it takes some time to build up a good hot fire that you can really cook on. The big downside is that you need to build up a fire-ring, you burn a lot more wood than you need to for the heat, and that ash is going to stick around when you're done violating "leave no trace". None the less, it's entirely viable in many situations where there are very few users, you have time (both for cooking and burial of ash), and/or you're camping in established sites.
Other times it's completely out due to limitations of fire hazards and such.
So, what do you do the rest of the time? Why are we carrying in fuel when there's perfectly good wood in many scenerios? The idea of being completely detaching from society is right there, but we can't because of time and environmental influence, what can we do about this?
Enter wood stoves. If we can burn wood really efficiently and completely we'll only need a few twigs, and the result will only be a tiny bit of ash. In many situations this won't cause anyone problems at all. Additionally, in so doing we don't need to wait to build up this huge mass of hot coals, because we're getting all of the heat out of the wood fast.
After a fair amount of research I picked up a Bushbuddy Ultra. More information can also be found on BacpackingLight. These sites together have give a lot of details, but the long and short of it is a 5.1 ounce stove with a double-wall firebox, an absolutely perfect draft, that won't scorch the ground. I ordered it with the matching titanium pot from backpacking light.
There are many woodstoves out there, and I haven't tried others. That said, the guy who desgined the bushbuddy is a tinkerer. He lives off the grid and spotwelds these by hand with a solar-powered welder and a home-made tip he developed himself. He's been perfecting the design for many years, and it shows. Additionally, the non-scorching feature is pretty rare and hard to find, this isn't something many of the stoves worry about, and those that do mostly don't supply sufficient heat isolation to achieve it.
So, the obvious question now is... how well does it work?
Well... wonderfully! Given a couple of sticks as long as your arm and as big around as my pinky (I have largish hands), along with some good dry grass or similar to get it lit, I can boil a liter of water in about 10 minutes best case. At worst it may take more like 20 minutes to get it all lit and the water to a hard boil. So far we've mostly used dry manzanita and live oak brush. This is some of the best wood you could have. The worst conditions we've used it in is a dewy morning. So we'll have to report back later with more thorough results.
With a stove like this there's no reason not to really cook your food. Even with those 2 sticks much of the wood used is in getting it up to heat, once it's hot getting a rolling boil is very fast. I'm sure that I can simmer on it with more skill, but I'm still working on that :). So far I'm still carrying my alcohol stove (at a cost of some fraction of an ounce). This means I can use the alcohol if I just want food "now" or can't find wood. The alcohol stove fits in the top of the wood stove for storage, and in fact the wood-stove acts like a super-fancy perfectly drafting high-tech windscreen, greatly improving the efficiency of the alcohol stove (sorry, I don't have numbers on that yet).
So, now that I've raved, what are the downsides. Well, the downsides are as obvious as the upsides. Although this is FAR easier than getting an open fire lit, it's still a heck of a lot harder than an alcohol or butane. You need good tinder. Surprisingly, supposedly you do not need very good wood. I've successfully boiled water using twigs from small dead brush, and I've heard you can use worse. The stove is very well built, and very robust under expected forces. That said it MUST be protected in your pack, the outer walls are extremely crushable sideways (not in the way your pot will put force). I expect it to last for many years, but I'm very glad I got the pot to store it in. Another downside you might expect (though not think of), unlike an open fire you're not going to be doing any baking in the coals. The biggest downside is the pricetag of $145. Handcrafted and designed by someone this meticulous it's worth it, but it 'aint cheap.
Jess plans to try her own designs and compare them to the bushbuddy, expect upcoming articles on the results of those experiments :)