You can clone successfully using just water (place cutting in a container with water and wait). So Rapid rooters, Jiffys, cloning gels, cloning solutions, special mediums like rockwool, perlite, etc. none of that is necessary at all. The one disadvantage to cloning in water is that it takes 2 to 3 weeks to see roots, but you can cut this time by at least a week by adding some kind of bubbler to the water... which actually makes you realize all the "cloning machines" are confirmations that cloning in water with a lot of airflow is the best method indeed.
If you want to use gels, keep in mind the absolute best gel is not Clonex, Rootech or whatever but Aloe Vera. That's right, get some gel from an aloe vera leaf and use that in your cutting. Aloe vera has a natural blend of vitamins, minerals and auxins that is like using a man-made gel plus Superthrive. Try it and be amazed. Don't have an aloe plant at hand? Use your own saliva as gel, just put that cutting in your mouth and give it a nice coating with spit. Seriously, saliva speeds up root development, look it up.
If you want to use powders, remember that the lowly el-cheapo kind is best, because cannabis is an easy to root plant and as such needs very little auxin to do it. This means that the more auxins you give, the longer it takes to root. That is the reason you are better off using a cheap powder, because those typically have only 0.1% Indole 3 Butyric Acid. With auxins, less is more, and that's the reason also that you shouldn't spread Clonex like grape jelly all over the stem, but only the exposed area (that's why it is a good idea to do a slanted cut, to maximize contact with the auxin). Clonex' 0.3% IBA is actually too strong for cannabis, it's meant to work with brittle woody cuttings, so use only a tiny amount on the exposed area (f you paint the entire stem with Clonex, it will swell and become mushy and have difficulty developing roots).
The real factors for cloning success are none of the above, but the following:
1) Moisture (below and above ground, not wet in either, mist the dome, not the leaves)
2) Low Lighting (too much will force the unrooted cutting into photosynthesis and will die)
3) Bottom Heat (should be between 74 and 82 degrees constant, no wild swings)
4) Blue Spectrum Lighting (fluorescents are best, especially if the light is filtered through a paper or cloth)