Is you Mac lagging? A quick flushing-out of the RAM can help speed-up things. And Memory Clean does just that.
Instantly gives your Mac a boost
Memory Clean flushes out your RAM and displays your Mac's full memory stats in the menu bar. In just one click, your Mac's memory is purged. The developer recommends using it when you close an intensive app that you do not plan to use again for at least a few hours. This way, it ensures that no remaining processes or activity from the app is hogging your RAM.
The necessity of such RAM-purging apps is hotly debated. Many consider it unnecessary as OS X does the best possible job of managing RAM effectively. For those with at least 4GB of RAM or more, this is probably true but for those using less, or using extremely RAM-intensive apps, Memory Clean may give you a temporary boost.
Makes flushing RAM easier but it's not essential
Memory Clean doesn't do anything that can't be done via Terminal either. You can purge your Mac's memory very easily using Terminal rather than Memory Clean but it does make the process slightly quicker, plus it has the added bonus of the Menu Bar RAM monitor. However, Memory Clean explains very clearly what is using your RAM and for those unfamiliar with Terminal, is a much better option.
Quick way to boost your Mac - but use with caution
If you're having severe problems with RAM or memory hogging issues, Memory Clean is worth a go but it should be used cautiously.