I don't really trust. I prefer to edit myself.Agree but this freeware also provide backup feature of which it is useful. Of cuz you can do that by hand but it would mean more work and how to keep track of the changes you had made? With these software they help you keep track cuz every time you perform multiple changes to registry, a backup reg file is saved for you to restore any time.
Since it is free and it comes with backup feature I prefer to use it. It is not very huge. Of cuz CCleaner looks to be an overkill and hence I did not install it
