Worst free choice? Try the popular and widely acclaimed free Roboscan 2.5. No product update since Nov.2013, obsolete BD engine (v11.0.1.6, currently .12) and BD def updates every 24 hours. It does have their Tetra engine with 24-hour cycle def updates, too. But no product update since Nov.2013. They do have their Proactive Detection Technology, too, but did I mention no product update since Nov.2013? How much worse does it get? Oh yeah, they often miss their def updates by days at a time, or a week or more sometimes.
While the BD side of things in Ad-Aware Free AV+ is hash based, defs updates occur in sync with BD with Ad-Aware checking every hour.
Ad-Aware is also a dual solution product using Lavasoft's Antimalware and RealTime engines, the latter having heuristics tech they once marketed as Helix and Genotype. As well, all Ad-Aware versions will run any suspected processes in a sandbox. Not so worst.
That said, I use Ad-Aware Pro (tower) and Personal (laptop).
I don't want this to go off as to what might be a more or less not so worst free choice discussion as 1) it's off-topic and 2) I don't do free AVs.
Cheers.
