My important email addresses have been protected by SpamTitan since early last year and I can't be much more satisfied with a product than how satisfied I am with SpamTitan. Be it the famous Nigerian Prince scam, or the more recent secret cryptocurrency mining malware that's been spreading around and affecting millions, SpamTitan keeps my inbox clean, organized, and spam-free. Major email providers seem to increase their security over time to protect us from spam and scam emails, but they are not perfect yet. This is where SpamTitan comes into play.
I like the complete protection SpamTitan provides. I can rest assured my data is safer with SpamTitan. Once in a blue moon it 'overprotects' and filters a non spam email as spam, but that rarely happens. Personally, I'd rather be overprotected than underprotected.
SpamTitan offers a month to try out their services. Make sure to use this generous offer and test if it works for your organization. Support is very quick to respond to any issues or questions.