"Registry Cleaner" is a very popular name since that is also the category it falls into...registry cleaners. Thus, it's important to know who the author of the program is for identification purposes. (Alternatively, the download link.)
Until then I can't compare it to Registry Mechanic, but I can comment on the latter. It is one of the most powerful and thorough registry cleaners available, and widely popular. My only discrepancy is that it returned a lot of false-positives in my tests, suggesting the deletion of registry entries crucial to the operation of Microsoft Encarta, among other things. Thus, I only recommend it for those who know what they're doing so they can look over when it finds and deselect anything that shouldn't be deleted.
Hope this helps,
John
I recieved a trial of Registry Cleaner; is it legit and how does it rate against Registry Mechanic?

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