BLUF: A bit over priced but it does what it says and is very useful.. It is a little annoying that it has advertising for it's other products built into the user interface displays. I paid for this... I should not have to deal with ad-ware. Never the less, a good utility, good features, helped my misbehaving macOS 10.12.
Details: The interface is clean, easy to use but with enough tech-extras to make it appealing to the hands on person as well. The tech extras are subtle, try right clicking on screen elements...
This utility can perform the clean up and more importantly it can leverage the Finder to show you **exactly** what it is cleaning up. The tech-extras show do this with the magnifying glass and various path names that it both displays and yields back.
What I particularly like is the ability to collect all the macOS sprawl into one place. Like Windows, there is now junk *everywhere* from installers, and in many places now that are hidden from the user (like Services menu item in the Finder or "Launch Agents" not to be confused with "Login Items" which users can see). Management of macOS has become a part-time job and CleanMyMac is a great assistant for things that are simply not worth your time to mentally track.
Free version has enough features to make it a keeper even if you think $40 is too high. Tech extras are there too which make it a worth while keeper. But be careful, you might find yourself using it enough to say "oh heck I could use the rest and they do deserve to get paid for a job well done". Then you go looking for coupons as CleanMyMac does issue discount codes periodically, up to 50% off as I have seen.
Recommendation: Impressive clean up that actually works. Use with intelligence, watch what you are cleaning. - 1 star for the adware integrated into the user interface.
CleanMyMac is cute and clever – however there are far better utilities that do the same thing for FREE. – A former customer