I have been using Onyx for many years, and have found it to be stable, frequently updated, simple to use, and the automation features are great.
This being said, it is your own responsibility to ensure that you are not using a BETA version, and UNDERSTAND what you are doing to start with. I would suggest that you NOT randomly begin to delete various system and kernel caches, etc, unless you are CERTAIN that you want to in order to cure a specific problem. Or suffer the consequences.
This is a great tool, that allows access to many parameters that would ordinarily require Terminal.
I consider this to be a "must have" tool.