AVH stops the majority of spam on my blogs. However, what I've been noticing as of late is that all the spam comments that make it through AVH have used new IPs that haven't been blacklisted yet but have used usernames and/or email addresses that appear multiple times on one or more blacklists.
In one case, a spammer that managed to get through AVH on my blogs used a username that appeared 32 times in one blacklist alone, but because the IP he used was "fresh", he managed to get his comment through to moderation.
Another spammer that got through used a username that appeared 3 times, in combination with an email address that appeared 6 times, both within the same blacklist. But since the IP used during the spam attempt was fresh and unblacklisted, the spammer still got through.
It would be great if you'd consider adding an option to AVH that enables it to take into account the frequency of usernames and emails on a blacklist when a visitor attempts to post a comment.