I have several clients who use phpBB and other forums and they are being killed by spam attacks. Several have been spammed so badly that they have removed the forums and it seems to get worse. Now I have another client who wants a forum but I have been hesitant to set it one up up without good spam filtering. How effective is PunBB against these horrible attacks. In one case, I have a client who has a site which has mostly women visitors and she is disgusted with the endless porn spam attacks. I am hoping PunBB is effective against these robot attacks where the captcha doesn't stop them.  I'd like to hear some peoples experience or get advice on how to reduce the spam on PunBB.
thanks,