I downloaded it just a couple weeks ago, because my MacBook Pro is still showing the beach ball constantly. I only performed a permissions clean up with it and it seems OK. But I have to do a back up before I play with it anymore, I wouldn't fool with it unless you have backed everything up first just in case.
16 GB in the Other category is not a problem. That just means that you have 16 GB worth of stuff that isn't in one of the other categories (Audio, Movies, Photos, Apps and Backups). That includes the system and many of your personal documents.
Your Mac does not need cleaning. See The myth of the dirty Mac.
(Note that my pages contain links to other pages that promote my services, and this should not be taken as an endorsement of my services by Apple.)