For freeing drive space by removing unwanted temp folders and wiping the offline IE content in order to free up drive space I never found anything wrong there.
As for a registry cleaner that won't break anything however the free automatic cleaner Eusing has been put up against several others and found better at finding more items as well as moving a bit faster. http://www.eusing.com/free_registry_...ry_cleaner.htm
The removal tool from Adobe was a good catch there since that was written specifically as a remover for their programs. Not too many 3rd party uninstallers are that good and tend to still leave things behind. I hear this from others who work with the registry on a regular basis as well.