Grisoft renamed themselves to AVG Technologies a while back (a year or so)
http://free.avg.com
It's still there, with the same terrible detection rates it had before.
AVG 6 and 7 were both decent, though 7 you could tell it was weakening slightly. These two I benchmarked against the Symmantec version at the time and McAffe by connecting a known-infected removeable drive to a system that had them installed.
Symmantec failed outright, it did not detect the virus until it had already infected and done damage- and then it was completely unable to remove it. Not only that but this Antivirus behaves like a virus itself, being near impossible to remove and tampering with system internals so heavily that some user applications experience compatibility problems.
McAffe knew it was there from the start and refused to allow access to said file. I had used a very old version of this back in the days of Windows 98 and was kind of glad to see it was the same intermediate result that it had back then.
AVG found it right away as well, but it also was able to clean the infected file and return usable data.
Based on the result of that I've been using AVG ever since. But I did notice Version 8 seemed to be weakened further than 7, and when 8.5 came out I was like "Yeah version 9 is going to be garbage."
Haven't tested version 9 yet, but usually when a product starts to go downhill like that they don't come back up right away. I will benchmark version 9 just to be sure, but am leaning towards no longer recommending AVG.