After, using System Mechanic 10 Free, I do not have any reason to replace CCleaner with System Mechanic. All the feature less or more are available in CClaner. The only one feature is Memory optimization which may be a reason to use SM10 Free but this is not a strong reason to use SM10 Free. I still give CCleaner The Best Free PC Maintenance Suite. If you want to use System Mechanic 10 Free, used with caution. It is found very aggressive when cleaning Windows Registry.