I did the soil thing,.. it worked fantastic for the first year, it even seemed to add quite a bit of CO2 to the water,.. but the downside is every time you uproot a plant it makes a total mess of the tank. GREAT for low maintenance tanks, but for a tank you tinker with it is less good.
I have yet to find a perfect substrate, Florite is good, but benefits from root tabs (Or osmocote frozen in ice cubes works even better and is practically free), Fluval Stratum is good, better from a nutreant standpoint I think, but it is lighter and doesn't hold the plants down as well. It too ran out of nutreants BTW, and needed fertcicles eventually.
I really think EcoComplete is nearly 100% inert, but it also works well with Osmocote or root tabs.
Nutrient wise potting soil is probably the best, but it makes the water yellow in the beginning and makes a mess when you uproot stuff.
It's kinda like "Pick your battle".
If I had to put effort into one place it would be first CO2, second Light (not lots, but just enough to find a balance),.. Then I would think about substrate and water dosing to make sure the plants are not limited anywhere.