Yeah, I've used it a few times successfully. As others have said, mix in a good percentage of perlite (maybe 25-30%) to keep the medium airy. Those roots need some space to move around and the perlite helps with that.
When using FFOF, I wouldn't feed my autos for about 3-4 weeks...just used plain PH'd water. The soil is nutrient-heavy and can even stunt seedling growth. Happened to me a few times but the plants recovered just fine.