I've used floramax (FM) for years, and it's fine. Definitely better than gravel and sand for a planted tank substrate. It's essentially the exact same stuff as Eco Complete (EC), which is a more popular version and made by the same company, only differences are:
-EC comes with a liquid in the bag that's supposedly beneficial bacteria. FM is just dry, so no liquid weight if you're comparing price to weight ratios.
-Due to the liquid in the bag, EC does not require a pre-rinse.
-FM needs a major pre-rinse and after you flood the tank, you'll need to use the included bio-magnet packet to help clarify the water from the particulates that will cloud the water for a couple days. This will settle and subside, not a big deal.
, when comparing EC vs. FM, I'd get either -- just which ever is cheaper. Both are semi-inert at first, so I used flourish tabs when I initially setup my planted tank with it.