Currently I've got my adults in a mixture of good potting mix and about 60% or so medium sized perlite. I've heard that using a soil-less media such as orchid bark is better as long as it's a good brand. I've currently got my 2month old babies in some good potting soil with perlite in 3" pots.
I use clay pellets. They reduce the risk of rot. MG keeps them blooming.
I also use the clay pellets and it is a method called semi-hydroponics. You have to use the correct type pots for it that are plastic with 2-3 holes about 1 inch from the bottom. I have about 70 plants in it and I love it. There are very few caudiciform or succulents that you can't use in it. It did cut down my rot problems by about 90%. I have used this method for well over 10 years.
