Rat 5 is good read some reviews online with grain of salt
Zack you know your budget and application best, but there are dozens of reviews that you can google that compare similar knives. Many on youtube are a total waste of time and a few are very helpful. This text article probably tells you everything you already know: http://www.blackscoutsurvival.com/20...-3-review.html
My personal 2 cents is that if you already have some good small knives think about paying a little extra for a 5" or 6" cutting blade (full tang) Ontario RAT 5 is a good choice IMO. (1095 steel) Search Amazon and other retailers for best price including shipping obviously. These may not be the best if you are an ultra light backpacker or scuba diver; obviously a tool should match its intended purpose. Flint blades work better for skinning animals etc but I would not want one for batoning small branches with. blah blah. I can survive in many warm forests with only a thin bladed machete but that would not be fun. Buck saw and small knife are great, and hatchet or axe in a northern forest is very helpful especially for dead wood.
Edit add video:
http://youtu.be/aMSlEoV8ZBw
DIY buck saw, make with your knife in field or at home
If pack weight and size and or cost is an issue consider making a buck saw. Using a relatively small/medium knife (full tang is best) to create some notches in sticks helps. But ideally you would take a compact buck saw with you that is very fast to assemble in the field. There are many other threads and comments on this forum that discuss these but here is a good DIY instructional video. There are 100+ others. I liked this guy's idea of using an aluminum crutch from a thrift store cost about $1-3. High quality Swedish blade is great but one you can buy in almost any local H.W. store may work out better for most people. Also some places online sell S.S. or Ti split rings such as county comm dot com.
http://youtu.be/p02ErrjTCj4
Bushcrafting your own buck saw in the field with only knife for your saw blade on split rings is fine but it takes time, and I prefer to spend this time collecting wood and making a shelter when possible.
2.3 cm I.D. may be enough to go around aluminum pipe that is available to you or from H.W. i.e. 1/2" O.D. plus saw blade but check to be sure before ordering from DX, "Etsy", ebay, amazon or where ever. Here is one source there are many others, these rings are handy.
http://www.dx.com/p/simple-stainless...7274#.VKLsNBoA
just don't order those tiny ones for fishing lures.