There are so many things that make this plugin THE plugin to have.
If you don't think so you haven't looked at it.
First, VERY easy to use and they do all of the setup work so you are more protected than other plugins right off the bat.
Keeps you updated before any other plugin like it that plugin updates need to be done.
Blocks out hackers automatically when they use usernames you don't have.
Shows you live traffic and the easy ability to block IP, range or entire server.
Emails you when ANYONE logs into a site (can show client THEY logged in at a day and time and screwed up the site)
SOOOOOOOO many other things. Free version is awesome, inexpensive paid version is phenomenal!!!!