I use it as a first layer along with fine Profile sand, among other things, in a 75. The mixture is topped with Eco-Complete. Plants take hold quite vigorously and clearly push their roots/rootlets into the soft + squishy Florabase granules, something they cannot do with Eco-Complete (though as you’ve likely observed Carlos, roots still grab the Eco granules more enthusiastically than with Flourite presumably because of the extra porosity). Like other substrates of its consistency it is extremely clean despite its softer makeup. I have it as a sole substrate (with N/P & humate additives) in a 10 and it’s been good so far, but not remarkable.
Can’t comment on its usage alone sans any other additives; I haven’t used a naked substrate (i.e. Flourite with zero additives) for some time, so it’s tough for me to offer cogent remarks on FloraBase-only vs. Flourite-only. (I’d add that I’ve seen older tanks with Florabase as the primary substrate and noticed compacting and breakdown of the granules, particularly in the lower to bottom-most levels. This was one reason that I decided to use it as a base in the 75.)