You don't particularly NEED maintenance software on a Mac, but CleanMyMac (especially the new version) is not so bad actually, it's certainly not a scam semi-malware like MacKeeper and has actually som neat functions and design. I ocassionally use it for certain tasks (such as uninstalling apps, removing languages or slimming iPhoto library) and it never hurt my system. As I said, you don't really need it, and I don't know if it's worth the $30 but I got it with a significant discount and I don't regret that purchase. I wouldn't totally condemn it at once.