Or the best Reg Cleaner on the planet?
hmmmm,,, thinking,,,,,,,,,,,,,, nope,,,,,,,, can't think of one............... still thinking..........
Nope, doesn't exist.
Reg cleaners are and will always be for the most part, snake oil and relegated to the farthest reaches of mythicism.
With that said, using something like CCleaner to do some minor cleaning of some things is not bad, when it is actually needed, but it has been proven that Reg Cleaners have a tenancy to do more damage than they resolve.
PS.... The one located on the link above (OneCare Site) is really the only one I would trust,, and I had forgotten about that. Why? Because it is developed by MS, they don't have this all out ambition to blow anything and everything away from the registry just cause some programmer trying to produce a (so called) better product thinks those things should be removed.
Registry cleaning is not something that should ever be done as a regular maintenance cycle, it should be done when it is absolutely necessary due to major issues with apps and the OS as a last resort before a Nuke and Reload.