So, back on topic. Very happy so far with the STG Hail 1" cubes.
Unlike rockwool, STG cubes are safe to handle without gloves. STG does not escape pot drain holes & make a mess in trays & tanks like Fytocell. You can keep Fytocell from escaping pots by putting a thin layer of rockwool floc in the bottom of the pots, but this alters the drainage & water holding characters of Fytocell. STG does not hold as much water as Fytocell, so it can be flooded 2x (or more when plants have gotten large) per lights-on cycle. I have yet to run plants through an entire flowering cycle in the stuff yet, but so far, it looks really promising.
Don't know how much the stuff costs, but even if it's a bit more expensive than Fytocell, it'd be worth it for the ease of handling & cleanliness factors alone.