Spamassassin versus DNSBL

Until now I've only been using spamassassin as my personal spam-fighter. Messages are tagged by spamassassin when he thinks its spam. This works quite well. As part of its tagging spamassassin uses DNS blacklists which is ok. But having a relative slow DSL-line I now use something which works even better in my case. I'm now using the dns-blacklist feature from exim4 to reject incoming connections from known spammers. I just added this file (04_exim4-config_dnslists) to the /etc/exim4/conf.d/main directory and now my debian host automatically rejects the incoming spam (see /etc/exim4/conf.d/acl/30_exim4-config_check_rcpt for more info about how exim handles this)