Quantum reels with the ACS braking systems usually ship with a great deal of Hot Sauce grease on the braking surfaces. Every new one I've ever seen is just gooped up with the stuff. If this stuff is still on your reel I recommend setting the ACS to it's highest setting, removing the side plate, wiping off the braking ring in the side plate and the tabs (weights) on the side of the spool. Use a little Zippo fluid or Ronsonol on a paper towel or kleenex to help get it really clean. Open the side plate and clean again after several casts because the stuff will continue to work out of the spool weight assembly. This should improve the response of the braking system. You can also polish the ring with some wet 1000-1500 wet-or-dry sandpaper and/or metal polishing compound. The weights will brake more efficiently on a smoother surface than on a rough one. Also, try setting the spool tension so that when the rod is held straight out with the handles up and the spool is released that the weight does not initially drop, but when the rod is lightly flexed, the weight/lure drops about a 18" and stops. Start with the ACS on the highest setting and back off as you build confidence. When everything clicks, you'll be glad you stuck it out.
daj