The biggest difference between SaneBox and a Spam filter is that a Spam filter should be analyzing the contents of emails looking for malware, viruses, phishing, etc.
Why can’t SaneBox handle Spam?
We don’t look at the content of the email so we cannot do that, nor do we want to. Also, we do not segregate emails that are unsolicited. They are sorted into Sane folders like the rest of your mail.
However, SaneBox does pull most everything out of your Inbox that a spam filter would except for virus emails from friends and associates who have had their email hacked and well crafted phishing emails.