I had experience in the past with Barracuda and WatchGuard. Barracuda was fine, although I found it harder to configure and administrate. Less intuitive, but possibly more robust. WatchGuard was a nightmare, it either blocked too many things or not enough, and the rules were …
Sophos Secure Web Gateway has flexible pricing and deployment options. It offers a huge range of categorization options and they also pull web categorization info from other services.
Sophos Secure Web Gateway is great for almost any business that needs an easily-manageable proxy server. We're a medium-sized enterprise, but the product would work great for much larger companies as well. The only real limitations would be hardware resources, but it isn't that intensive. The administration of it is very intuitive, and it was quick to set up. Where it might not make sense is across multiple sites, unless all internet traffic is funneled through one place. It would be a bit complicated to maintain multiple setups.
Administrator Permissions: There's not enough granularity on the administrative side. We ran into an issue where we wanted to restrict junior admins from being able to see traffic per user. But in doing so, it also prevented them from adusting some other settings they had to have access to, like setting exceptions for sites.
CA Database: I occasionally run into issues where the list of certificate authorities in the appliance is not up to date, and I have to manually add a CA. These aren't rare, never-heard-of authorities, either, but they are usually subsidiaries of one of the major ones.
Feedback: Sometimes it takes some good detective skills to track down why a legitimate site isn't working. It's often because of content hosted elsewhere (images, for example), but the reports aren't always clear as to what actually gets blocked. It takes some trial and error sometimes to unblock something that should be okay for our business.
Sophos Secure Web Gateway has flexible pricing and deployment options. It offers a huge range of categorization options and they also pull web categorization info from other services
We have not had a single instance of malware since installing Web Gateway. We have other ways to prevent infections and attacks, of course, so this is just one tool in the box, but we had a handful before this from people visiting sites they should not have. Web Gateway has prevented those, at least.
There was some pushback initially as users had to deal with some business sites not working (usually due to CA problems). After the initial growing pains, however, we've seen very few other problems.
The appliance updates itself, in the middle of the night, so that reduces some overhead and planned downtime.