I have used a lot of the system utility programs, and Ace Utilities personally was not one of favorites. First off, the user interface was very clunky. The programs and accessories were not organized very well, and changing to a different set off tools was a lor easier on other programs I have tried. Not only that, but Ace Utilities didn't seem to be nearly as effective as Registry Mechanic or Fix-It Utilities. When I did a registry clean, it said it only found 30 errors but could only fix 10. Whereas, only a few minutes later it I ran one using Registry Mechanic and that found 60 errors and could fix them all. I could not find any significance to Ace Utilities, and comparing to others I have used it was not as good.