Prior to 1.4 this was an essential plugin. Most of us would like to see its functionality continue to live on. But it remains some of the best money I have spent in regards to Xenforo. I needed nothing but this plugin and the core features to keep spammers at bay.
Don't want spam with that? Then this is THE utility to stop the bots at the front door. Author provides great support and is very responsive to feedback. You can't go wrong (but I'd suggest getting the full package of all his utilities).
My site was targeted by spam bots a few days ago. I received about a 100 spam registrations in few hours which was something I have never seen in 7 years as forum admin. Some really awesome friends here recommended that I install this add-on and I did. Now it's been about 2 days and not one spam registration made it through. Seriously this is the best xenforo add-on investment I ever made. I highly recommend it. Great customer service too!
Been running this for about three months now. I've never had a spammer on my forum and I don't use CAPTCHA, so I got curious and checked the logs.
My forum is private. There are five legitimate user registrations total. The rest were created manually through the admin interface.
There are 1,600 entries in the FoolBot log. All blocked registrations detected from spam bots. This addon is the real deal and the best spam protection I've ever seen on any web app. If you're using the free version, seriously considering buying this to support the dev.