That's kind of the impression I've always gotten. There's even a thread about some problems with Fox Farm stuff somewhere on this forum. They're just very much a soil-first kind of company.

If I were growing in soil that'd be fine. But I just don't think it's a top-3 or even top 10 choice if you're using hydroponics. You can spray pure hydrogen into the intake of an automobile without any gasoline and start the engine. But you'd have to be insane to try to operate it like that without a serious alteration of how that engine is built.

rhizome has it right - you need the right tool for the right job. Or at the very least the right kind of tool for the job. What's your favorite hammer isn't quite as important as not trying to drive nails with a pipe wrench. IMHO, FF is a pipe wrench in the nail of hydroponics.

But if you're just looking for opinions, I'm a AN Grow, Micro, and Bloom guy. I'm a chem salt guy too - I've just never seen anything that indicates a plant cares (or even knows) the difference between NPK that came from lab salts or was broken down from organics.