Looking through historical reports from the testing institutes such as AV Comparatives and AV -Test it becomes quite apparent that no single product can claim or be claimed to be the best as their performance differs from test to test. What can be seen is that there are 5 or so paid products that consistently offer high levels of protection.
These are in no particular order - Norton - GDATA - Bitdefender - F-Secure - Kaspersky
AVAST, despite the protestations of some on this forum routinely outperforms quite a few well know paid for products.