type f fluid has less friction modifiers than dexron or mercon fluid. many racing transmission rebuilders like to recommend it to reduce friction wear an achieve a firmer shift. as of late, some also like john Deere hydraulic fluid, which i believe is also synthetic or part synthetic(lowers stall speed a little too)
type f fluid does not hold up well to heat, and does not lubricate as well as conventional fluids. personally i do not recommend it at all. I don't believe in sacrificing lubrication for firmer shifts, and in some cases firmer shifts cause more harm than good. there is also no et gain from using type f fluid. There is no loss in transmission clutch holding power using synthetics or dexron, don't let anyone fool you in believing so.
synthetics are a excellent choice, and fluid temps are reduced with synthetics, but as mentioned they are expensive. Many of the late model fluids in new vehicles are also very good fluids to use (atf+4, dexronVI, mecronV)
