This stuff is very expensive but I started two weeks ago. The jury is still out, but seems very effective for "normal" acne, less so on cystic acne. Though it does seem to tame cystic acne/flatten it slightly, not as effective as cortisone shots.
Cystic acne is very resistant to topicals, that's why antibiotics, steroids, anti-androgens, and/or Accutane is commonly prescribed for this.
From what my derm told me when I was using Aczone, it helps with redness, not much else. It should be used in conjunction with something else. That was my understanding anyway. Glad you're getting some improvement with it though!
It's always a good idea to use Aczone with a retinoid.