In 2012 I needed this plugin and I liked it very much. It's the only one in its kind.
But this plugin isn't updated for over 1 year now. And developper is not available on supportforum at all. So I don't update my (extensive) webite because I'm scared what will happen with this plugin..
Also, if you have a lot of restricted pages attached to a lot of usergroups (25 groups or more) the website is very slow.