We were hacked a couple of weeks ago on two different sites, both running latest versions of everything and both pretty 'secure' as far as we were concerned .... obviously we were mistaken !!!
After cleaning everything up, we did a lot of research to see what we could do to mitigate things, both in terms of prevention and recovery, but also in terms of highlighting potential issues that may have managed to get through. This plugin, along with Bulletproof security always seemed to come up in the list of best products.
We have installed both across several sites now and feel a bit more secure. The plugin highlights even simple changes and easily allows you to view exactly what has changed and revert to a default version if something is not quite right.
Willingly gave this 5 stars in the review and about to purchase the paid version as this is a product that is worth every penny of the small fee asked for.