This is a great plugin. Don't let the whiners who gave it 1 star detract from that.
I can't stand it when I hear people whine and complain about how bad support is for a free plugin. This guy tries VERY hard to help everybody, and the plugin is very high quality. He's not getting paid for this, and you can't expect him to be available to answer your questions. You should feel LUCKY when you get a personal response, not entitled to it.
This plugin does incredible things, and some of those thing are risky. Making something secure is always very difficult. You risk breaking something that was working before for the sake of making it more secure. You also risk making something more difficult to use for the sake of making it more secure. If you care about security, then you need to accept these risks. There are warnings all over the place telling you to be careful. If you don't know what you're doing, stop doing it and get somebody to help you. And stop complaining about the guy who is making an excellent plugin available to everybody for free. If you're one of the whiners reading this, what have YOU done lately to help out the WordPress Community? I bet the answer is absolutely nothing.
When I read some of the problems people have had, it makes me wonder if they should be using WordPress at all... maybe they shouldn't even be using a computer, because it's way to complicated.