Used spamassassin for a bit at home.
We've got some money budgeted for this, so we don't need a freebie - we need something that isn't going to fall over every three minutes, which is what spamassassin did for me.
"Many that live deserve death. And some that die deserve life. Can you give it to them? Then do not be too eager to deal out death in judgement. For even the wise cannot see all ends." - J.R.R. Tolkien, The Fellowship of the Ring.