Actually, I find that 1.3 and 1.4 still have issues with determining spam. While fairly decent, one still has to go through looking for false positives. The other issue is that spammers have been doing a good job at designing emails to fool filters. I'm starting to see more and more spam designed to defeat Baynesian filters. By including "good" words in their emails, they either make good words spammy so that you get more FP's or they make their email clean enough that it's still in your inbox. The worst part of it is that spam is quickly becoming unreadable, so that legitimate emails that are readable are the emails more likely filtered.
I hope I never get your "legitimate" email. :) Since about 100 messages I practically stopped visiting the Junk folder every now and then because no false positives occurred. Just for the sake of this message, I peeked into the folder and scrolled trough the last ~300 messages and all spam. About one in 50 does not get flagged and this stream has already gone through the basic checks like that sender needs to have a legit domain name and such. So I´m happy camper and I hope that legislation catches up with spammers before they figure out a surefire way to defeat Baynesians. Pete