Personally, I've had pretty good success with Jon's old Uline bag method. This was the one that used screened perlite and a little promix or other peat based potting mix and prewetted before bagging.
I tried that method and the same method but with screened perlite and fine chopped spagnum moss and then run water through the bag initially. I found so far that the prewetted mix with perlite and peat potting mix has had far better results and to the eye, the perlite and spag seems to have too much moisture in the bag and also the top inch or so of the bag dries out quickly, while the lower part has too much moisture so rewetting becomes difficult because water flows though it so quickly, it can add to the high moisture levels in the lower part of the bag.
As far as mold and rotting, I've become more and more convinced that in most cases, the issue is the quality of the cutting more than anything else. What I mean by that is that if the cutting is fresh and the tree has been protected from frost damage, etc. then success rate with little mold seems very high. On the other hand, trees with some frost damage or other sources of dead wood on the cutting seem to struggle with mold, fungus and rot early and often. IMHO
I haven't tried the riot cubes yet or mini-SIPs for rooting. They're probably next to try.