I used the Esbits along with my Trangia Alcohol stove for a couple of years before I switched to Pepsi can stoves in 2000.
For me they were a great alternative to my whisperlite.
The esbits tabs can get expensive at $.50 each, depending on where you can get them - Plus shipping. (campmor, southsummit.com, etc). I remember getting ready for a week on the trail - I needed only about 20 tablets 1 each in the AM & PM and several backup tabs which weighed in at about 10 ozs - Very light.
I like that they can bring 2 cups to water to a boil in about 8-11 minutes and that they are very stable and you can fly with them. Also, you can put out partial tabs and save them for later.
However, I don't think they perform that well in the winter. You might get a cup of water boiled, but when you want hot water fast and more than a cup, you really need a stove designed for it. I think the heat output of the Esbit would have a hard time trying to overcome the heat loss in extreme cold.
I would absolutely avoid the Coughlins or any other tablet. The heat output is miserable - You need about a 3:1 ratio of other tabs to compete with Esbit, also the others reek and they leave a sticky residue on your stove.
FWIW, I really like my pepsi can stove - when traveling, I pack a candle with it and it becomes a newfangled candle holder. In addition, any 7-11 stryle quicky mart carreis the yellow bottles of Heet, which is perfect for Running the stove on.
Good luck
Rick