I can only speak to the Barracuda v300 (the virtual version of your physical appliance). I've used various anti-spam filtering and AV scanning/security products over the last 23 years, and for all the faults of the parent company, the Barracuda Email Security product is pretty darned good.
UK antivirus company Sophos has bought Canadian company ActiveState for £13.9m in cash, adding ActiveState's line of antispam products to Sophos' enterprise antivirus software. Sophos Email is a secure email gateway engineered to keep businesses safe from all email threats. It simply stops spam (AntiSpam Protection), phishing, malware and data loss and keeps your people productive.
They recently disabled the inline password pass-through for users managing their quarantine through email, that's a serious bummer. Otherwise, the smart attachment blocking/quarantine is pretty easy to implement, the overall performance is really good, and the feature set very complete.
For my personal email server, I use another product that is server based, not appliance/vappliance based (since 2004, incidentally). Also, due to the SIGNIFICANT expense of Barracuda maintenance subscriptions, my work secondary MX is filtered by a competitor. I've also used several other mail filtering & security products over the last couple of decades at different client sites.
Sophos stops everything malicious and provides us with alerts, so we can respond quickly—and that’s worth its weight in gold.” Cliff Hogan, CIO, D4C Dental Brands Switching to Sophos Central was a simple transition and 80% of the work was carried out within just one week.” Andy Bone, Head of IT, NAHT. PureMessage spam rules may fail to download for several reasons. The following troubleshooting steps guide you through the most likely reasons for this problem. Follow them in order. Important: Ensure the Sophos credentials (available on your license schedule) include the PureMessage Anti-Spam component. Sophos has provided steps for Outlook, Thunderbird, Mac Mail, and advice for Lotus Notes. Microsoft Outlook First, make sure that your Outlook is configured to not send attachments as winmail.dat files as SophosLabs cannot parse those submissions.
I had a Sophos SG appliance for a three year period, and I did setup the POP3 proxy for a few users from a company we acquired in that period. I was very 'meh' about its performance. Having used Barracuda, I didn't find it an equivalent, and was happy to pay for the much more performant product despite the additional significant cost.
Depending on the size of your shop, I'd really look hard at avoiding an on prem appliance and moving to their cloud product. A buddy of mine has MANY of his clients on the Barracuda Cloud and is quite pleased. We have enough users and bandwidth that it's not important to us, but having some mail service continuity might be a deciding factor for you. It's NOT free to have a secondary MX on a separate ISP, let me tell you! That cost component can make the cloud offering less costly in comparison.
Use the Configuration > Policy > Anti-Spam page to configure how to handle messages with spam characteristics. A cumulative spam score is assigned to each scanned message based on results of anti-spam tests. This score determines the relative likelihood that a message is spam and classifies messages in one of three ways: not spam, medium probability of being spam, or high probability of being spam.
The Policy: Anti-Spam page allows you to handle Mail with high spam scores (almost certainly spam) differently from Mail with medium spam scores (probably spam), and bounce messages.
Sophos Antispam False Positive
Each row of the Anti-Spam policy configuration table is a policy rule with options for defining the relevant users and the actions to be taken. By default, there is one rule defined for each of the two spam categories. Mail with high spam scores is discarded for all inbound messages, and quarantined for all outbound messages. Mail with medium spam scores is quarantined for all users. Mails which encounter spam engine errors cannot be sent to the policy engine, and hence, are quarantined.