I tried Esbit, one summer in an ultralight frenzy to get below 15 pounds, and found that it worked best if you had a good, 360 degree windscreen around it, fairly close to the pot and running up the sides. In cooler weather, I never did get a boil - heat loss to the air offset the added heat from the Sterno, and everything just kind of stalled out.

I have a friend who has one of the new pot-windscreen Esbit cookers, and he's had very good luck with it - in fact, it's now his stove of choice. It also has a tight windscreen, so you get all the heat into the bottom of the pot. He does have to deal with storing a tablet that hasn't burned completely out, occasionally, and they do stink. (It's important to note two things: we hike in the Ohio River Valley areas of Ohio, Kentucky, and Indiana, and we only do add-boiling-water-to-a-bag cooking. There's never food in his pot.

I prefer a canister stove and, except on a couple of occasions when we called our sanity into question by heading out on 10-degree nights, have never had any issues with it. (On those nights, it still worked, but we had to stick the canisters inside our jackets, and they were sluggish even then.) Down to 15 degrees or so, I've never had any trouble with either the Jetboil, MicroRocket, Pocket Rocket, or Snow Peak Gigapower or Litemax stoves. (Boys and their toys, as my wife says.) They all seem to work fairly well. My current favorite is the Jetboil Sol, only because I like the insulated pot cozy (keeps my tea warm longer)and because its burner is screened enough that it doesn't seem as susceptible to breezes. (But, I've never had any particular trouble finding a spot behind a rock, log, or tree to minimize the effect on any of the other stoves.)

However, discussion with Lori (who doesn't like Jetboils, based on her experience leading trips) in another thread has me pulling out my Jetboil Litemax stove and titanium pot for my next trip to save a few ounces - my trips aren't long enough that the Jetboil's efficiency means I can carry one less fuel cylinder. And, if I find I really need a pot cozy (which, mostly, I don't), I can make or buy one for the Snow Peak pot.

Long story short: I'm not sold on Esbit, but my friend is. I've never had any real problems with canister stoves, and really like them - and it seems that one is about as good as any other; just match the pot supports to the pot you use.