Why do you think you need it?
Here are some opinions at reddithttp://www.reddit.com/r/mac/comments/2hefvo/memory_clean_vs_memory_diag/
Both utilities work by requesting enormous allocations from the system, forcing it to drop any optimizations it may have made in terms of objects stored in RAM as cache, or worse, forcing it to swap other allocations to the hard drive.
OS X knows what should and should not be stored in RAM, much better than either of these utilities do. The reason you normally see your RAM full when as rest state is simply because free RAM is wasted RAM. Undoing any of these optimizations is going to make performance worse, not better.
Go to Activity Monitor and click on the Memory tab. Check the graph at the bottom labeled Memory Pressure. Have you ever been in the yellow or in the red? If not, then you don't need either or any of these apps.
Let the OS manage the memory. You'll get better performance if you do.
Now, if you are in the yellow, or red, that's a different story. But in that case, neither of these apps are really going to make much of a difference. Instead, you have to consider if everything you have running simultaneously is necessary. If the answer is yes, or if all your memory (reflected in the Memory Pressure graph) is used by a single app, then the answer is to add more memory.
It doesn't seem to be malicious, and may be interesting to look at.
But in most cases it doesn't seem to be helpful for speeding up your Mac.