I'm using Avast and find it very good. Testing sites/forums suggest it has a slightly higher detection rate than AVG, and not as good as the other big freebie, Avira. Avira is extremely good, up with the better pay for A/V's, but doesn't incorporate an email scanner in the free version. You can make what you will of some of these tests, they're all around the place, have varying criteria and I think, at best, give a pretty good indication. The real test is how protected the average user is against viruses in the wild, on regular internet surfing, and for that, Avast, AVG, and Avira are generally quite adequate. In addition you need a firewall, preferably outbound as well as in-especially if you're a high risk user, and a resident antispyware program is advisable.