It was a little bit hot for my seedlings (but only a LITTLE bit, a few nute burn spots here and there), once they took hold they seemed to love it. I'm just wrapping up my first real grow and I had some plants in roots organic and some plants in FFOF, but they were all started in party cups with FFOF. Could not tell a big difference between the two, but a more experienced grower might have been able to.
My plants seemed to like both soils very much. FFOF is a pretty good bet, maybe start the seedlings in something a little bit lighter on the nutes though