So I've tested this tool myself, and I can say that it's a pretty nice and quite useful gadget. It clears a bit of ram every time you press a button, but you can also set options like "clear every 5 minutes" or "clear when ram usage is higher than 80%". Didn't recognize any disadvantages.
But: it doesn't clear the ram usage of MTA. This means it won't help you if your problem was a limit of RAM usage for the MTA process. My limit stayed at 3,7 GB (after 3 hours of playing) and my game freezed. But it helped with other programs like photoshop, which also takes up to 2 GB of ram when you use it for a couple of hours. It cleared the memory usage completly and it started from 10 MB, without any disadvantages like losing data or closing files.