Yes, I use Auslogics Registry Cleaner, CCleaner, and Glary Utilities registry cleaner. I been cleaning my registry with these 3 programs and my computer seems a bit more stable and fast.
I don't think cleaning registry is that important, but a disk defragmentation every week is highly recommended.
Well that is true,most registry cleaners make a back up before hand.Some people recommend you do, but other people recommended that you do not clean the registry since there is always a chance of messing up your computer if the "registry cleaning program" accidental deleted a wrong key. If every thing on your PC is working fine, then cleaning your registry won't make much or any difference to your home PC.
I just found a website that sells registry cleaner programs for 30$!