Using the WildList as their dataset, Virus Bulletin discovered that 17 of the 32 failed, including some very popular suites from vendors like Trend Micro. Some of them were disturbingly bad, such as CA Home, which had 40 misses. You can read more about the benchmarks they use as well as the most recent study at their site
How much do you trust your anti-virus suite? And moreover, do you believe that pay products versus free products in the anti-virus world have more robustness? It seems that is not always the case.