The reason for registry errors being different (increased or decreased amounts) across different programs are numerous:
Some count missing entries or entries not pointing anywhere as errors
Some do not do the entire registry but just parts of it
Some look at cache (like last opened entries) as errors
Some look further than the registry and even check other areas in Windows
Actually, if you check out CCleaner registry button and run it, you will see that you have many options to select\deselect
So who's telling the truth?
This all depends upon what you define the word "error" as
ie MUI cache is not an error, actually the contrary, cache entries help us know what the last known data or program startup was, for easy access. Such as Recent Files in the Start menu.
I find CCleaner to be a basic, registry fix only (well it has a little bit more

) But it's generally safe to use, and therefore to be quoted to others. I have seen registry fixes rip through the registry removing user settings ; effectively putting Windows program startups to default (ie Windows Media Player back as the default video player)
I have even seen, where programs such as Notepad will not open again, because the association to txt or log etc files were removed
Therefore just running a range of them to view the results can have disastrous effects on Windows. Again CCleaner in default setup, is very safe as a registry repair. Plus it's an excellent cleaner of temp file locations (ie its real purpose)
I would suggest to stay with CCleaner, and only venture out (try alternatives) at your own peril, as each is not exactly the same as the next. And may in fact do more harm than good. Registry editing\removal or fixing\repairing is generally a sensitive area at the best of times.
