The degree of customization and logging with SpamTitan is amazing. You can account for everything going in or out of your organization and set filtering rules to match any scenario. Performance of the web UI and functions like searching and reporting are lightning quick. Virtual machine for VMware was super easy to deploy. Spam Titan offers an in-house solution, which we LOVE as well as options for people who prefer cloud. In-House appliance has full support for ipv6 both sending and receiving.
I recommend to take the time to consider SpamTitan. The offering is flexible and if you still want and trust an in-house solution, they offer that in addition to cloud. The in house solution is not scaled down in any was and is just as good as the cloud offering.
Barracuda spam filtering was letting us down and letting viruses through. As a Managed Service Provider we wanted our own in-house solution for spam filtering we could use our self and resell to customers. We didn't feel like paying some other company to do it for us in "the cloud". Spam Titan was the perfect fit.