Ccleaner is popular for a good reason. (It's good, and does what it says it will on the packet.)
It includes a fairly safe registry cleaner (termed "issues" in Piriform parlance) that makes a backup by default, before any reg entries are deleted.
I can't speak for the other reg cleaners you refer to. Another I've used that I consider safe is called "Tweak Now". Some reg cleaner are fairly non-discerning, it seems, and now and then will delete a reg key that is actually required. Best bet is to not use them unless you've learned a bit about the registry, and thus have a bit of an appreciation as to what the 'worst case scenario' might be if any particular key is deleted.
In some cases this will simply require re-installation of an affected program. Most serious scenario is that a repair install of Windows might be needed. You'd have to be a bit unlucky for that to happen.
A program I would recommend is
ERUNT (by larshederer) that automatically backs up the registry at every boot, or when commanded. Some users use this in lieu of System Restore, it's that good.