Not really ... I don't get infected computers all the time that are using AVG/Avast!, but I do get them in occasionally. Most of the time w/ AVG, it's trojans that AVG catches but doesn't completely remove, so the infection keeps coming back (Detection rate and removal rate are both important //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif). I don't get computers in w/ common problems using Avast, just randomly misses viruses it seems.
Both AVs are perfectly fine for the occasional user or the smart user, but the ones in between should be running something better, IMO (the people who download lots of stuff and don't know WTF they're doing).
We sell dozens of computers a month at work that go out w/ Kaspersky and I've yet to see a single one come back w/ a virus infection. That says something. We get 1-2 a month that have problems w/ the firewall, but that's easily fixed (For whatever reason, Kaspersky Internet Securty manages to add Internet Explorer to its block list. Still not sure why/how it happens).