Thanks George Oster for the warning about losing Finder comments. No need for the developer to bully someone who's giving a helpful warning like that, even if it was mentioned somewhere else. I've been heavily relying on Finder comments (now called Spotlight comments) because they really help Spotlight restrict its search to few keywords and find quickly what we're really searching for, as opposed to searching the whole content of the file which can be anything and everything.
I haven't tried Finder Cleaner yet, so this has nothing to do with the product, but with the developer's attitude.