While I don't consider a wire saw as "front line" equipment, they do have their place in your kit. If you have the space/weight, by all means it's best to carry a good folding saw. I have both a Sierra Saw and an Opinel folding saw; the Sierra goes in my ruck and the Opi is on my knife belt.
But the SAS wire saw, available from Brigade Quartermasters, is a good thing to have in a mini-kit. Especially since, if you're only carrying a pocketknife or 2 (assuming you're caught with just your EDC gear) you might need to cut poles for a shelter or firewood. To use the saw properly requires that you harvest a green bough, split both ends to insert the saw's handles, and then saw carefully. Using the wiresaw in this manner you can cut a surprsing amount of wood. Once done cutting, though, don't just take the saw off thes tick and roll it back up. Allow the saw to cool donw comletely and THEN roll it up. Rolling up a warm saw is a sure way to break it.