For me it is Mitsuda by far. Uematsu can be good but by and large he rarely reaches the heights that Mitsuda has. I can throw on Chrono Cross, Chrono Trigger of Xeno something and not want to skip much of what is there. I want to skip the majority of any FF OST (Though they work in the game). For me that leaves Uematsu as good but not great. Why this is, I have no idea?