This is a must-have plugin for anyone running a wordpress website. The free version is very comprehensive and fully functional. The paid version has a few extra features such as scheduling scans, blocking countries, and scanning remotely. I love the feature that allows you to see the difference between the original file and the modified file, line by line. This has proven to be very helpful as I have modified plugins and want to know if the alert is based on a change I made, or if there was an intrusion.