AVG Antivirus free is one of the most popular antivirus programs on the market. The company is moving from annual releases to rolling releases: as long as you have a subscription, you'll have the latest version of their software.
Rolling releases: In the past, buying a copy of AVG would get you regular antivirus updates, but features would not change until you bought the following year's version. Now you can always have the newest version of AVG.
It's free: Although it's release method has changed, you can still get a version that costs no money -- though there are a few strings attached (more on that in the Cons section below).
Modular installation: AVG has separate components that can monitor your desktop email client and your Web browser for threats, and you can choose to not install both of these, if you have other software that covers these bases already.
Installer gotchas: If you don't intervene by using a "custom" installation, the installer will put you on a 30-day trial of one of the company's paid products instead of installing AVG Antivirus Free. And it will change your Web browser's homepage and default search engine to Bing.com.
PC Analyzer has issues: AVG Antivirus features a PC Analyzer, which checks for registry errors, junk files and broken shortcuts that can be deleted, and disk defragmentation. The problem is, you're not supposed to defrag a solid-state drive, but PC Analyzer did not appear to notice what type of drive it was. The analyzer is also all-or-nothing; you can't skip the defrag or the registry cleaner and just delete junk files and shortcuts, for example.
According to independent testing labs such as AV-Test and AV-Comparatives, AVG uses a solid antivirus engine. But the hoops you have to jump through in the installer and the technical error in the PC Analyzer have an impact on trust and confidence in the product.