We first became aware of GFI back in the summer of 2003 when it was at version 8 and 9 was in beta-2 release. We eventually went production on version 9. Our environment uses Microsoft Exchange Front-End servers pointing to the Internet and back-end servers behind our firewall. In this “gateway mode”, the GFI product sits on the front-end servers and keeps SPAM away from our back-end servers which the users connect to. The product is highly configurable and allowed us to prioritize the different modules in execution rank. It is extremely easy to use and configure.
All version upgrades were very quick and painless. We went from versions 8 through 12 and kept the product updated with every released build. During the upgrades, the product actually uninstalls the older version (except for your configuration data) and then installs the new version. Unfortunately, it does not remember the answers to your previous installation questions and therefore asks them again. If you make a mistake (for example, on Active Directory integration), it can throw the entire install into trouble and you will most likely have to clear out all of the directories, registry values and start again. This is very frustrating, because the product does not warn you about any inconsistencies, but you will see parts of the UI change after installation that gives you a clue.
From the beginning, we were very impressed with GFI and our accurracy was well beyone 99.99% with respect to false positives and less than 2% of SPAM made it to our users. Our incoming mail went from about 30,000 messages/day to over 400,000/day and we did not degrade in those numbers until we hit version 12.