At first, I thought the plugin was great until I ran into these problems:
1) I was told there were too many login attempts from my computer when I have NEVER entered an invalid password when logging in to my WordPress installation. So, I had to wait 20 mins before I could login to my own WordPress dashboard.
2) Despite there being SEVERAL IP addresses logged with failed login attempts, the administrator e-mail account was NOT sent any messages so I had no clue the plugin was doing anything other than logging lockouts.
I'm not sure how this plugin gets the administrator account's e-mail address to dispatch notifications but it didn't work in my WordPress installation.
Problem #1 is a deal breaker for me. If I'm blocked from logging in to my own WordPress installation due to a failed login attempt I never made, I can't continue using the tool.