In my experience, it usually has been this way, at least with the Symantic products I used with XP.
QUESTION 1: If I don't want to pay $500. for the latest Enterprise AV technology, and am therefore stuck with signature-based, you are recommending Webroot instead of say ESET Nod32?
QUESTION 2: Why, from a technology perspective?
Mark H.
Webroot and Cylance are using big data, heuristics, AI, behavior recognition to identify malware. This method detects unknown malware (and known malware).
Eset primarily relies on signatures. This method only really detects known malware.
AV such as Eset, McAfee, Symantec are all based signatures with a little heuristics and behaviour thrown in. However this usually picks up minor variants to known malware. Not something completely new or a significant changed variant to a known malware.
This is essentially why people get raped by crypto-ware infections. They are usually changed enough to get past signature based protection.
Eventually the signatures catch up, but until they do there is a window of opportunity.
As an example, one of my customers is sending me samples that are coming into his email server. He is a reseller who manages IT for a handful of small business users. He currently scans with Eset, McAfee, Kaspersky, and Cyren. From this month alone I have around 30 new not seen before malware samples that sailed through the above AV engines. And remember this small business stuff from a single site in New Zealand.
How do I know they are malware? Because I'm testing a new email scanning version of one of our products and it picks them up.