I use a base which is a mixture of clay and vermiculite topped with a layer of sand.
Your choice would be dictated by:
- types of plants you are trying to grow: the more demanding ones would require more nutrients, substrate that allows more gaps for roots to grow easily, etc. If you are using more demanding plants and want to go for a high tech tank, then I would recommend the ADA, Ecocomplete route. If you dont mind slower growing plants then you have a choice of laterite, clay, other clay substitutes.
- budget - ADA and Eco are more expensive
- complexity of aquascape
- your adventurous nature

- are you willing to try experiments with different types of substrate? After all the plants in the wild grow in simple soils, mucky environments!!
I hope this helps you decide.