The type of soil you should use must be tailored to your conditions. Where there is regular humidity and/or rains, moisture control types are likely to remain too wet, hence blackening, rotting cuttings. If you're rooting them indoors or otherwise under cover, moisture control types will also probably remain too wet. In my conditions, humidity is fleeting and rain is not reliable. My cuttings are grown outdoors, exposed, with no cover and temps in the past month have mainly been in the seventies to high eighties. Only the past several days have been colder and even with the "rain" we received yesterday, pots are drying out quickly due to the drying winds following the bit of rain. I use the moisture control type soil so my cuttings don't fail due to drying out in a day or two. The only issues I have with the moisture control soils are when I pack the pots or bands too tightly with the soil so they don't drain well enough. There are nearly three-hundred cuttings there now, many already showing roots at the pot bottoms and all potted in the moisture control soil. If I was rooting them under cover, I would likely use something more along the lines of a seed starter mix. Sequoia Nursery, EuroDesert and Burlington, who all used/use mist propagation, used propagation and growing medias which were primarily perlite with some bark or "potting soil" combined. It was extremely loose, providing some moisture retention with excellent drainage. The problems I've had in my conditions with their plants were primarily due to their drying out in a day or two unless I replanted them in moisture control soil. It all boils down to selecting the right type of drainage for your conditions.
