I am a huge fan of CCleaner, but I saw where Comodo is now offering a free cleaner. I downloaded and tried Comodo System Cleaner. I ran Comodo after running CCleaner, and Comodo found an additional 500 registry problems, even after CCleaner had fixed all problems it found.
What is Comodo looking for that CCleaner is not? I hope that Piriform is looking at competing products frequently to see how they work, and to see what improvements can be implemented in CCleaner.