So, recently I have been building my emergency kit. As part of this I have gotten some emergency fuel, both for heating water and as firestarter. I bought both Trioxane Fuel tabs and Pyropac Gel Fuel.
Here is a quick review/comparison.
TRIOXANE

Trioxane was originally developed for MRE packs to heat a canteen cup of water and also the meal packs of MRE's. While they light will and burn good, in general, they didn't put out enough consistant heat to boil water or heat the MRE packs. However, since modern MRE's come with their chemical heaters, I was thinking of these as firestarters. In that role, they are AWESOME! I got some brush together, stuck a trioxane tab in the middle, and struck one match. Within minutes I had a roaring fire.
They work MUCH better than the **** firestarter sold at grocery stores, are cheaper than the camping firestarting tabs, and come in individually sealed packets. They are are also extremely light. Note that there is a size different from the tabs (1" square), and the bars are about 1" by 2 1/2". But tabs are about half the cost, so decide what you want, more smaller ones or less larger ones. These are a great buy at .79 cents for a tab, compared to commercial stuff.
I bought 18 of them for my emergency kit (except for my one test tab) here:
https://www.mainemilitary.com/productcart/pc/viewPrd.asp?idcategory=0&idproduct=2276You can also get them with the Folding Stove, and I have actually picked up a couple of them too, but just for the stove. I will use the trioxane as a firestarter, and keep the stoves as backups to heat water with more effective water-heating elements (see below).
http://www.cheaperthandirt.com/MLT9089-1.htmlPYROPAC GEL

This gel pack acts a lot like sterno, but in a more easily "spreadable" format. I think this would be much better for boiling water/heating food/etc because it burns with less flame and more heat the the Trioxane. I tested it again as a firestarter, this time I used it on damp wood, and it worked great. I made my pile of damp branches, and then spread the gel around. The slow burning hot flame did a great job of getting the fire going, and soon I had a good blaze going! It's downside is that it is quite a bit heavier than the Trioxane, and I could see the packets getting smashed and maybe blow out.
http://www.cheaperthandirt.com/MRE202-1.htmlFINAL CALL:
The Trioxane is an AWESOME firestarter. Buy them now! But I wouldn't get them to heat food/water. I would defenitly grab these if weight was an issue. It is also really cheap, you can get 36 tabs for $8.99 from Maine Military Supply.
The Pyropac is a great firestarter, especially with damp wood. It is also my choice for heating food/water. However, they are much heavier than the Pyropac, so I probably wouldn't choose them if I had to hump it. A little more expensive than Trioxane, but still very reasonable.
For my kit, I have both, neither are expensive, If I had to choose, I'd probably grab the Trioxane because of it's lightness and the fact that I have newer MRE's with packed-in heaters and stored fresh water, so I would mainly be looking for a firestarter.
Hope this is helpful.