This is a really nice extension, which does exactly do what it claims to do. A nice way to add a Captcha to your site wherever you want. I've referenced this in an article that I wrote for the upcomming Joomla! magazin and I'm using it in my own extensions.

I really like this module. It has all the switches and functions I want and from my point of view, its easy to use at the beginning. If you want to use the more advanced functions however, it gets a bit confusing. The documentation is not really extensive.
I especially like the possibility to split menus to different module positions and the patTemplate support. Makes it so much more easy to adapt.