I knew that I was going to be sitting beside the river all afternoon and evening today so I took a bunch of small portable saws with me to play with. This test was completely unscientific and just involved me using each tool to determine which one I liked best; I am constructing a new pocket Personal Survival Kit and needed to know which one to include.
The saws were, in smallest to largest order:
-Coghlins 8 strand "Commando" wire saw with wrist straps.
-Carbon hacksaw blade (the teeth are fine, about 24/inch)
-Reciprocating saw blade (10 teeth to the inch)
-Leatherman TTi saw (not in photo, Duh)
-Swiss Army Knife (SAK) Farmer model
-German Army Knife (GAK) Saw (old model)
-SAK Rucksack model Saw
-SAK One Handed Trekker model saw
-Bacho Laplander Folding saw
-Sawvivor Folding Saw
The tools can be seen in the image below:

Small Survival Saws (sorry about the flash spot)
I tested the saws on green poplar and dry cherry. About the size of wood you would use to make a lean-to shelter, 2 - 3 inches in diameter.
I started with the wire saw, and even though I have had luck with them in the past it was a complete failure today. It bound-up and cut very poorly, only cutting in about 1/2" before it got very tough to pull. The crimped-end connector then broke; so I constructed a bow saw out of it but it did no better, I will not put these in a PSK again.
The wire caw is not to be confused with the flexible "Chainsaw in a Can" type saw which I know cuts great, I just could not find it in my storage area today to include in the test.
The hacksaw blade and reciprocating saw blade also did poorly, they would have cut better with a proper handle, but they did not bite into the wood well and the teeth got clogged. Poor choices.
I expected the German Army saw to do better and it did, but the kerf was a little too wide, the blade short, and it only cut on the pull stroke; it was still not great.
The Leatherman and all the Swiss Army Knives (SAKs) can be lumped together. They all cut well for there size, the longer the blade the better they cut. They all cut through 2" of dry cherry with minimal effort, very functional tools for small material, short term use.
The Bacho Laplander folding saw was amazing compared to the smaller saws, it cut through a 6 inch dry cherry limb with little effort. Excellent tool.
I am a little undecided on the Sawvivor, it cut well once I got the cut started but tended to bounce in the beginning due to the coarse teeth. I think it would have performed better if the wood was held more securely, I need to test it some more.
In conclusion; the wire saw, utility blades and especially the German Army knife were disappointments. I will now need to reconsider my proposed PSK container to accommodate a larger tool, either the SAK Farmer or Rucksack I think.
As always everything we use is a compromise, function vs portability.
Mike