Not sure why this addon isn't getting much love on here. This is by far the best tool to mitigate spam registrations I have ever used. Very effective and very well thought out. Keep up the great work mate!
Probably the best anti-spam add-on we've used on any forum. We originally tried out this add-on as one of the vB4 testers in 2015, blocking over 700k bots between 2015 - 2019. Since migrating to XenForo, we've sorely missed this add-on, so were pleased to see this now released for XenForo 2. Since installing on our site several weeks ago, we've seen spam immediately drop from around 10+ bots per day managing to register, with most being able to post, down to 0 successful spam bots registering or posting on our site.
For us - this add-on is a must have, and we'd strongly recommend this to anyone with an active site.