MrShed:
Scrimper - disagree, on two fronts.
Most AV have been using Heuristics for years, and certainly it isnt the only free one to use it.
Secondly, by far the highest rated freebies (by detection percentage, which ultimately is what its all about) are Avira, AVG and Avast - in that order.
Eset isn't free
Yes, many other AVs use heuristics WHEN you perform a deep scan. However when you initially download a file, they only perform an initial scan based on signature detection.... so the virus can go undetected until the next scheduled deep scan is performed.