The author, Keith Graham is also really helpful and attentive on the suport forums.
The new version 4.1, to be release any moment is also greatly improved.
Currently this plugin is preventing over 30 spammers/spamming attempts PER HOUR on one of our BuddyPress community sites. We simply couldn't contemplate running without it. And neither should you.
Worth every penny of any contribution you might consider making for it. Or buying one of Keith''s books! :)