1. For the cost of the paid software, I can not see going free when you can pay as little $16 a seat w/o sales or discounts. However Windows defender has made great strides here. Since we left BD, I been getting offers as low as $17 for 5 seats. Never renew... just buy as a new customer... much cheaper.
2. One thing about AV providers... building a better product gets them more sales. And starting with Norton in the 90s, to bitdefender today. once they get to the top, sales stabilize and they gave to look for new ways to increase profits. That means overly restrictive usage restrictions, bloat and difficulty uninstalling. We stopped using BD when I started having to download to each and every client, instead of installing over the network. BD and Kaspersky consistently sit at the top at AVtest.org. kaspersky doesn't make owning a site license difficult .. yet
3. The following products scored top scored 6.0 Protection / 6.0 Performance / 6.0 Useability all the data below is from the site, the last category Ownnership burden reflects our experience with each product
https://www.av-test.org/en/antivirus/home-windows/
Avira AntiVirus Pro @ $6.77 per seat per year w/o sales 3 years 5 devices
Protection against 0-day malware attacks - 100% / 100%
Detection of widespread and prevalent malware discovered in the last 4 weeks - 99.9% / 99.9%
Impact on Speed High End PC (5 categories) - Average - 8.8%
False Positives - 1
Ownership Burden - Unknown
Bit Defender Internet Security @ $9.33 per seat per year w/o sales 3 years 5 devices
Protection against 0-day malware attacks - 100% / 100%
Detection of widespread and prevalent malware discovered in the last 4 weeks - 100% / 100%
Impact on Speed High End PC (5 categories) - Average - 10.0%
False Positives - 0
Ownership Burden - Annoying time eater for installation / Occasionally gets fudged and getting it completely uninstalled can be a significant effort.
Kaspersky Internet Security @ $8.00 per seat per year w/o sales 3 years 5 devices
Protection against 0-day malware attacks - 100% / 100%
Detection of widespread and prevalent malware discovered in the last 4 weeks - 100% / 100%
Impact on Speed High End PC (5 categories) - Average - 9.4%
False Positives - 0
Ownership Burden - None
McAfee Internet Security @ $17 per seat w/o sales 1st year
Protection against 0-day malware attacks - 100% / 100%
Detection of widespread and prevalent malware discovered in the last 4 weeks - 100% / 100%
Impact on Speed High End PC (5 categories) - Average - 8.6%
False Positives - 0
Ownership Burden - Pain in the A$$
Vipre Advance security @ $17 per seat w/o sales 1st year, 5 seats
Protection against 0-day malware attacks - 92.2% / 100%
Detection of widespread and prevalent malware discovered in the last 4 weeks - 100% / 100%
Impact on Speed High End PC (5 categories) - Average - 8.2%
False Positives - 0
Ownership Burden - Unknown
Avira Free AntiVirus
Protection against 0-day malware attacks - 92.2% / 100%
Detection of widespread and prevalent malware discovered in the last 4 weeks - 99.9% / 100%
Impact on Speed High End PC (5 categories) - Average - 10.8%
False Positives - 2
Ownership Burden - Been a while but no significant problems when used
Windows Defender
Protection against 0-day malware attacks - 100% / 100%
Detection of widespread and prevalent malware discovered in the last 4 weeks - 100% / 100%
Impact on Speed High End PC (5 categories) - Average - 10.2%
False Positives - 2
Ownership Burden - None
BD, Kaspersky and others now have a new Family Pack option that allows anyone in the home to use BD on as many devices as they own (PC, Mac, iOS or Android device)... for Kaspersky, its 20 devices... but here kaspersky adopts the same PITA download to each device on network. Don't know much about these yet.