Anti-Spam

I’ve been using SAproxy for the past couple of months. It’s a POP3 proxy based on SpamAssassin; it runs locally on my PC and analyses incoming e-mails for likely spam content before they hit my mail client. It adds an X-Spam-Flag: YES tag to the headers of the message, which my mail program then uses to divert the messages off to a folder that I can safely ignore.
So far it’s been good. Every message that it has identified as spam has indeed been total crap. However, it still lets the odd unwanted message – probably one in twenty – into my Inbox. I can tweak it to judge incoming mails more harshly, but then it might start generating false positives. It’s been good enough for the time being and I haven’t been looking actively for a replacement.
Today I read about PopFile, which does a similar job but in a slightly different way. Functionally, PopFile’s benefit is that it doesn’t just tag messages as spam, it can tag them as anything that you want. It “learns” how to recognise messages and then allocates them into “buckets” (categories) by using Bayesian probability analysis. So, you can “train” it to recognise spam, but also messages related to your bee-keeping hobby (which could be a mixture of mailing lists, solicited mailshots and, uhm, bee-chat from friends).
My mailer is good enough at filing incoming messages into specific folders, but the attraction of PopFile for me is the promise of spam-recognition accuracy that seems to approach 99% after a week or two’s training. However, SAproxy is doing a reasonable job at the moment and so I’m only interested in switching if I’m going to notice the difference. Does anyone have any experience of PopFile, especially alongside experience of SAproxy or SpamAssassin itself?