Mac users can chose from half a dozen anti-virus apps, most of which are free or dirt cheap, but they don’t have much to do. There are no in-the-wild Mac viruses to worry about. Also popular these days are the cleaning and optimizing apps, such as Mountain Lion Cache Cleaner.
Perhaps to justify the nominal price tag, MLCC has a growing number of such features– cache cleaning, maintenance, optimization, customization, anti-virus (open source ClamAV), and even disaster planning (is that a good selling point, or what?).
Are these functions necessary on a new out-of-the-box Mac?
The answer may lie in how paranoid you are about problems. Apple builds into OS X all the maintenance, cache cleaning, and basic options they think most users need.
Mountain Lion Cache Cleaner extends beyond Apple’s default settings by making it easier to scan for viruses, repair permissions, automate a few maintenance chores, remove unwanted files (gains disk space), and customize your Mac here and there with functionality that Apple built into OS X but turned off.
As to disaster planning, one function I like in MLCC is the option to create a bootable emergency disk which can start up your Mac on its own, and comes with some additional cleaning, and optimizing functions.
The advantage to using MLCC is that many options are located in one place. It’s also a trial-before-you-buy app, which means you can see how it works before paying the price. If there’s been an improvement in performance on my two-year-old MacBook Pro after using MLCC I haven’t been able to detect it.
So, it’s back to your level of paranoia. If you feel better after using a utility that cleans, customizes, optimizes, and checks for viruses, go for it. It’s money well spent.