I have been very happy with version 4.9.
My only complaints are that there is no scheduled scanning (unless you run a cron job from the CLI) and the Enterprise Console does not serve Macs like it serves Windows.
Nitpics are the aesthetics, and the some of the terminology they use to define cleaning, protecting, and quarantining.
The aesthetics and terminology are smartly addressed in version 7, but they still failed to add scheduled scanning.
Also in version 7 the enterprise console still can't do what it does for PCs, not that I really care.
More of pain is the fact that they will be discontinuing support for 4.9 on 12/31/09 and version 7 does not support OS 10.2 or 10.3.
I have only been using version 7.02 for one day, and it seems to work fine.
Despite the criticism, I think it is the best anti virus for Mac!
The review stars are for version 4.9, version 7.02 would get another star for "Ease of Use", "Documentation", and "Features" "