registry cleaner?

ok ,ok, I get it….so one person says,NO leave the registry a loan… some else says, use with caution….and an other says, it’s ok…it’s safe……..dose anyone know for shure what registry cleaner safe ???……or do I have to pay to have the job done.??

They recc bringing box in if slowdown are that massive (I am luck the shop is a couple blocks away and these guys provide support all the time). I grew up with Windows hearing approach Registry with great caution, etc. These programs always seem to find "Deep Registry Problems" I have error expert (full). cc cleaner, and have tried other "free trials."
Advertising is so heavy for these things it is hard to find a straight unbiased review that addresses the basic question: Do not us, OK to use, OK but dangerous, Helpful as maintenance, Only if problem – etc.
Is there a simpler answer. Thank you very much.
jbyz