I have just started testing this on three forums I manage and I must say it is very impressive and very effective. Contact Form spam has always been the weak point in Xenforo's anti-spam features and nothing else I tried was able to stop it. Contact Us Spaminator works as advertised. In less than 24 hours, it has blocked more than 30 contact form attempts on the three forums. I don't own the three forums where I am testing it but I will be encouraging all of them to buy a license and certainly the first 24 hours is convincing evidence that they should do so.