It’s crap. Total and utter crap. When I last depended on Mail.app’s filtering I got practically no spam. Now I get about 3 spam messages a minute and Mail.app hasn’t picked up a single one, despite having been trained on a weeks worth of spam. SpamBayes was handling it perfectly even back when it first started. I’m really not sure how much longer I can put up with this before I’m motivated enough to divert my work email through my home server and filter it with spamassassin.