I use Miracle Gro Cactus Palm and Citrus Potting Soil but, not stand alone. The fact that palms and citrus would do well in this soil tells me it needs a little "fluff". My fluff of choice is perlite because its cheap and readily available. I grow my cactus mostly indoors and this mix works perfectly for me. But, I will admit, I am not a good plant Mom. My succulents and cactus have to survive on neglect.
My Miracle Gro to perlite ratio depends upon what I'm planting. If its a palm or citrus, as is. But most succulents (Jades, Echeverias, Aeoniums, Aloes... ) about 1/4 to 1/3 perlite. If its a cactus, it may be up to 1/2 perlite. I have an old Euphorbia I was warned not to overwater so, I planted it in about 3/4 perlite and 1/4 cactus soil (Hey, I was worried!). It now fills a 15 inch pot.
If you choose to mix your own, remember, the cactus/succulent is not going to look at the price tag or how much time/effort you put into making the perfect soil mix. They just don't care.
No matter what you choose to use to plant your cactus and succulents, the important part is it be free draining and fast drying. I don't think there is a 'right' answer. If you have ever been to the desert to see where most of these plants live, you would realize they are survivors. Its not your crappy soil mix that's going to kill them. But your perfect soil mix won't save them either.
