I have the spam-o-matic for 4.0 (running 4.1 pl2). Up until a week ago... had 0 spammers register. All of a sudden, I had 2 get through.... This, I think, due to spammers cracking recaptcha. A day later, another mod was created... so now I can run recaptcha and have a question/answer for human verification. 0 spammers since.
here is the spam-o-matic for 4.0-4.1:
https://vborg.vbsupport.ru/showthread.php?t=248042
here is the recaptcha/question mod:
https://vborg.vbsupport.ru/showthread.php?t=256782