Its a good question and one that I'm actively pursuing.
As noted in my other posts in this forum I've come to identify several categories for the current state of throwing knives.
1. Sharpened Sticks.
2. Circus Throwers.
3. Classic Designs.
4. Modern Designs.
5. Impractical Designs.
6. Hybrid Designs.
Sharpened Sticks
Like the name suggests, mostly just a rectangular or oval chunk of metal that has a point more or less ground onto it.
Includes both production knifes with no clear definitions for blade, handle or guard, and will almost always include things made from a file, lawnmower blade, random hunk of unknown and torch tempered metal and the subject of many YouTube Videos like the one shown here. Most often referenced as "look what I made! A throwing "knife".
[video=youtube_share;e-lm3mbWSjs]http://youtu.be/e-lm3mbWSjs[/video]
Circus Throwers
These are the "knives" that are designed to make you go "OOOOO" and "AHHHH" and be seen clearly from a seated audience position. Typically large headed, diamond spade tipped and usually handle wrapped with tape, cord or some other soft material. Usually involved with performance acts, or other such exhibitions. Zero redeeming value as a knife and typically one of the first designs you'll see when you search for "throwing knife"
Classic Designs
These are the ones you've seen over and over that all more or less trace back to Harry McEnvoy. They're great designs and are a kind of hybrid between sharpened sticks and circus throwers.
Harry made a ton of these style knives in all shapes and sizes but they all share the common elements based on his size/width/weight formula. (Search on ideal throwing knife weight and you'll find it... or check out Bobby Branton's site..) This category could just as easily be named "Tru-Bal". Many copies of this style of knife exist, even Cold Steel licensed Harry's designs and produced several of his models.
Modern Designs
Companies like Flying Steel, Condor Knife and tool, SOG, Gil Hibben and as noted Outback have come up with their own takes on classic designs and have created hybrids of hunting/thowing/bowie designs. Harald Moeller is famous for his VIPER line of throwing knives, both the swept bevel designs from the 1980's and his more recent re-takes on that design that he sells on his website now. These designs typically ad more classic knife elements of blade, guard handle and pommel into the equation.
This video and it's other series members shows a ton of knives that illustrate many of the categories I talk about here...
I'm not sure I agree with everything in it, but it does do a ton of show and tell.
[video=youtube_share;lCDq1p0IQrs]http://youtu.be/lCDq1p0IQrs[/video]
Impractical Designs
Cool knife! SNAP! CUT! BLEED!
Nuf Said.
[video=youtube_share;D7XNbVkfS1Y]http://youtu.be/D7XNbVkfS1Y[/video]
Hybrid Designs/Mountain Man
Made to throw, chop and slice, these designs come with a sharp service edge designed to be strong and serviceable. This is a Harry design again adapted by Cold steel but many bowie style throwers exist. They're typically used for camp chose, handle throwing and mountain man speed-draw competitions and the like. They come in a variety of sizes and shapes but typically all have defined and sharp edges, at least one and handles of some kind. Many have guards.
So, what is the best throwing knife that's not just a throwing knife? Personally I fall more on the side of the hybrid bowie side... but I have not found one that I want to own yet.
I've developed a design that I'm happy with as a thrower, and I'm in the process of testing its limits for other tasks. Really though throwing a knife is about as hard a task as you can ask of it short of clamping it into a vice and beating it with a hammer or bending it till it snaps. Its that rough.
My take thus far has been to segregate my throwing knives from my other knives, the same way I segregate my kitchen knives from my EDC knives from my hunting knives, from my pocket knives from my art knives.... you get the picture. I think throwing knives are no different.
With the mini-bowie design that outback came up with its an interesting if poorly executed product. 440c is a great steel if you're not going to beat on it. (Read throw). When beaten it tends to snap. Can you temper it so its fairly tough and resistant. Sure, have they? I'm not sure I want to spend $160 to find out, but I may, I am curious. I'm not sure of their warranty or what they'd do if I sent back one of their knives snapped in half, or worse yet, (My personal pet peeve) with a snapped tip.
People throw just about everything from Ka-Bar USMC knives to actual sharpened sticks.
Really when it comes right down to it I think a throwing knife should excel at tip penetration, balance, toughness and as much versatility as is possible without sacrificing its primary function. To be thrown, penetrate and stick like a demon. Have the attributes and qualities that is category of knife is designed for. Just like all the other categories.
Everything else will be a compromise of its intended purpose, which most of the time means a worse throwing knife.
Good luck, I hope this helps.
- Hal Zucati