SpamSieve has been serving me well. My Log reports a 99.2% accuracy rate, which is excellent by me. Virtually all my spam messages are detected and sent to the Spam mailbox. Only a few good messages are sent there, usually from a new sender.
I’m using the most recent versions of Apple Mail and SpamSieve.
After Mavericks, when I Train a “good” message, an action that formerly automatically sent such messages to my Inbox, they now just sit there, in the Spam mailbox. And they retain the Spam mailbox location in the description line. I have to manually move such messages to my Inbox or to some other mailbox.
Way back when there was a general issue that something had to be checked or some other action performed to have good messages automatically sent to Inbox. I looked through the SS preferences and didn’t see such a box, so maybe it was managed in another way. Please inform me.