Like I had mentioned before,  I have a really good saw in my Gerber exchange a blade that has served me well in any endeavour, so far at least.  I use it primarily in field dressing game and cutting wood for a fire.  I know I can rely on it to make any kind of shelter in an emergency, and replacement blades are cheap.  I had wanted to find a decent wire saw to include in my PSK for those times when I cannot carry my folding saw. After some fine comments from the crew here I see that a good wire saw probably doesn't exist.  I have come to be able to do almost anything with my knife and a good wood club in terms of cutting wood so I guess the wire saw is no longer an issue.  
Just out of curiosity, some of you have said that a Wyoming saw is better and safer than a Gerber exchange-a-blade.  I am not going to argue with anyone, as I am sure you have your reasons for saying this, but I would like to know why.