I am using this module and I like it but I can only give it three stars. I have the following criticisms:
1. Nowhere in the documentation for the more complex authentication methods is it clearly explained how you do the encryption.
2. We could do with more callbacks - I would like to be able to log successful and failed logins.
On the plus side the Dummy driver means you can easily set up all the visible stuff before you go onto the actual authentication. The generic driver saves the day because any monkey can at least set up a basic user/password system with that. I know it doesn't pass the highest security standards but horses for courses. There is a nice default login box (which as it happens totally clashed with my web-site's layout). Not a problem since only two options were required to change the style to fit in.
Overall I am both satsified and frustrated with this module - but it is marked as alpha software.
I evaluated this solution carefully and so far have decided not to use it. As with Cees' other published work, it generally feels well designed, documented and tested. For simple authentication, I felt like it was overkill. (It has whole modules to wrap the "uc" and "lc" functions!)
It seems like better fit when authentication needs or more complex, such as supporting multiple authentication methods.
It could also be a nice solution if you haven't designed an authentication system before and want a documented framework for it that illustrates all the parts of it.
The project is admittedly early in its lifecycle, and I look forward to seeing how it evolves.