I have used this for a couple of years.
It told me I had some significant security risks. I fixed them
I use it with their WebsiteDefender WordPress Security plugin and a few other security plugins and they all work together faultlessly.
It checks WordPress sites for security vulnerabilities and suggests corrective actions that are easy to follow. Obviously, to use any suggestions, you need to have some tech knowledge or be willing to learn it but their instructions are pretty straightforward.
I was staggered the first time I ran it - and I had already done a heap to secure my blog.
It is much more secure now and that has kept a lot of attacks out.
Well worth running it.