Originally MT-Blacklist required the Perl module Storable, which we didn’t have installed and I didn’t want to mess around with our server install of Perl. The newest version of Blacklist lets you work around Storable with an extlib called YAML.
I have Blacklist. Finally.
(I’ve gotten 200+ spam comments in the past day or so. I was starting to loathe going near my website again. Now, not so much.)
I’ve read of people having good anti-spamming luck by renaming some of the MT .cgi scripts (with corresponding template changes), and by enforcing a no-comment-before-preview rule. That’s apparently enough to default the simpler spam-bots.