Just as Coran said, you should try both out to see which one suits you best. I personally own a 2000 autococker(which i am selling by the way....check it out in the classifieds), simply because i want to go electro. My brother owns an Impulse and it is a great gun. It is accurate and quiet. The rate of fire is amazing(like capable of 16 bps). It operates on about 160 psi which is wonderful for the consistency and quietness. My autocker although it is consistent and fairly quiet, i am selling it because i played with my dad's shocker and fell in love with it. If you want a great autococker in my opinion your best bet is to go ahead and spend the money to get an upper-end one such as the free flow, but that all depends on how much you are willing to spend.