Mine would be Perelite. One I've had great success with was also marbles...seriously, marbles. Just wash them, soak them in some bleach and they work great. Make sure you get dark ones otherwise you risk algae blooms.
Hi.. I use a mixture of 25% hydroton and 75% of a silica (higromite or dynagrow) medium. I have had great results and I've heard that our ladies really like the silica. Just make sure that you soak the hydroton in 4-5 pH water for 48-72 hours before using, otherwise you can have Ph problems. Thanks
coco by far the easiest to manage. I run plants in 1 gallon bags in coco in a 3x3 flood and drain table.