And the best thing is that there are no 'hacks' or overwriting of core Joomla! files as many others require. I pulled my hair out (not too much to work with in the first place! :) ) trying to get the 'other' popular one to work and finally just wiped out the install and started over.
The key to getting this one to work is to follow the instructions on the site / forum. For full functionality, you have to install the SecureForm plugin, Auser, AContact and ALogin. Set them all up as per the instructions and you will have CAPTCHA-enabled User Login, Lost Password, Lost Username, Registration AND Contact emails!!! Fantastic!