um....dutast knocks DHT the fcuk out, like 95%, and has a long active life....finast is only good for about 80% (still, most) and has a <48hr active life.
most people dont need dutasteride...i use it on-cycle because i like to take DHT completely out of the equation, and replace it with something 5a-reduced but actually anabolic (anadrol, superdrol, var, etc)