I found SpamTitan via reddit 2 years ago and I cannot tell you how much time it has saved me. I am the sole IT person for a company of around 100 employees and before SpamTitan there would be days where half of my morning, every morning, was sorting through questionable emails that looked like legit invoices but werent.
In the last year over 170k crap emails were stopped before reaching our mail servers. If I scanned every one of those emails manually with 1 minute scan time each. That's 118 DAYS worth of time spam titan has saved me.
Their interface is to the point and not unnecessarily flashy. We use spam titan cloud and it is FAST. I can pull up a weeks worth of emails for all employees in 10 seconds and manually check if there was something blocked that shouldn't have been (rarely happens though).
I can view suspicious emails without needing to download them first, I can create custom block lists by domain or email address. And I actually just found a digest feature that let's me send all employees a quarantine report allowing them to unblock things they need from their own email without needing me to stop, find the email, and white list it.
Our plan has a set number of emails but unlimited domains so we have 4 companies using spam titan all under the same plan. I can add or remove companies on my own without messing with our cost or needing assistance from spam titan support.
Lastly, spam titan support staff are AMAZING. it's ridiculous how helpful and friendly they are. The most recent example being that my email host started acting up and emails were vanishing. Spam titan support, as well as my account manager for spam titan looked into our delivery logs and informed me what they saw on their end. They then went out of their way helping me understand how to setup another companies product to work with their own when they didn't have to.
I love these guys. The cost is absolutely worth the piece of mind and I'm a cheap skate to boot. I have never been happier with another company in my entire IT career.
I'm saving time, money, and getting the benefit of virus scanning before email even reaches our own firewall and network. In IT the biggest security risk is always employees unfortunately. This cuts that risk down for email alone by I'd say at least 90% making my job so much easier.