A Barracuda, like all appliances aren't plug-and-play, no matter what the marketing says.

Yes, they are easy to install and set up is almost plug-and-play but you need a minimal time to spend learning each system what is spam/ham messages. You need some time to set some preferences optimal for your email communication. And at the end, you also need to take a minimum of time for maintenance and write some filters and rules to block spam that Barracuda isn't detecting straight away.

Managed filtering service may also be an option for you. You'll definitly spend less time managing the anti spam appliance. I can recommend MX Lab, more info http://www.mxlab.be. It's a small company based in Belgium, Europe, that is offering it's services worldwide.