You don't always get the best results with free software.
Hmmm you dont often get the best results with many paid software's either (unless one happens to have Nod32).
And fyi, AVG free is actually paid software, its exactly the same as AVG 7.5 paid software except it doesnt have technical support and doesnt have additional features like anti-spyware and anti-spam etc...
And on the basis of that, AVG 7.0 (which is now 7.5) is an extremely good anti-virus, ranking above most others in the AV Comparatives tests and ICSA tests, the industry testing standards.
The one good thing AVG has over almost every other antivirus I know (bar maybe Panda and Nod32) is it has a really small memory footprint and isnt intrusive in what you do.
Its fine for an antivirus to be running on your system, but its no good if it starts using tens of megabytes of system RAM and loading the CPU, which a LOT of modern antivirii seem do, and which Nod32, being recommended as the best on the market, has proved there isnt any need for at all.