http://www.av-comparatives.org/ is one place to look for Anti-virus software evaluations. In particular, check their Real-World Protection Tests.

1. Go to http://www.av-comparatives.org
2. From the main menu, choose Comparatives > Real World Protection Tests. (http://www.av-comparatives.org/dynamic-tests/)
3. Download the most recent PDF (e.g. Real-World Protection Test March – June 2015).

That PDF is an evaluation of anti-virus software in real-world conditions. The report appears to be independent of any corporation. After reading the report, I generally recommend the free versions of either Avast or Panda. The former has the best rating; the latter has the best protection though tends to have more “false alarms.”

The reports are fairly long so it’s good to focus in on the most relevant sections.

• Tested products. This lists all the products that the report includes (it’s about halfway thru the report.)
• Summary Results. This lists how well each product faired. Pay attention to the PROTECTION RATE column. High scores are good here.
• Whole-Product “False Alarm” Tests > table. The table summarizes the number of false alarms each product produces. Low scores are good.
• Award levels reached in this test. This categorizes products into four categories: three star, two star, one star, or tested. Three star have the best balance between protection and false alarms.

Of the free versions, Avast generally scores as a three star and Panda as a two star (Panda is demoted because of more false alarms.) Go with Avast for an overall product fit. If you’re willing to have a few false alarms in exchange for higher protection, then go with Panda.

Aside: When installing Avast, choose “Custom Install” and install it without any of the optional Tools. The tools tend to be annoying, and if you later have need for them, it’s possible to add them then. Also, be sure to uninstall existing anti-virus software first. This includes Microsoft Security Essentials.