I have tried Epiweb both as a potting material and as slabs. I have had great sucess with a large numbers of species such as Pleurothallis, Dracula, Bulbophyllum, Dendros and Phalaenopsis. The roots goes very freely into the material and roots really quickly.
I have some Pleurothallis that grows like weed in it.
You must pay attention to the fact that it doesn't keep as much water as a traditional Sphagnum/CHC substrate.
But the risk of killing your plant by over watering is eliminated.