After years of using AVs, from Symantec era all the way to ESET, having tried them all, I will give my honest and humble opinion:
If you have Windows Defender with WIndows Firewall and Smart Screen, do not visit torrents/download pirated games and visit risky websites, you will be perfectly fine with that combo.
I have been a well known user of ESET, wrote an extensive guide in how to harden the ESET HIPS to its full potential. Have used combos like AV + former Emsisoft Behaviour Blocker (Mamutu) (you can even ask the staff here: I asked for a 1 year Mamutu license instead of other more common choices a few years back), having tested either Gnosis or Overkill's behaviour blocker which wasn't updated in over the years, was an avid user of CIS 5.10 and even used avg for its behaviour blocker. In the end I was never infected. I did a test back then for 2 months constant use of system without any AV, just Windows 7 + Smart Screen ( no firewall because I am a gamer and at the time, it did interfere with some of the games I played online. Results after 2 months AVless = zero infections.
So my recomendation is what I believe Hurracan always said: Windows Defender with firewall + UAC + Smart Screen + common sense is the best security. No need to over complicate things.
If WD is not enough for your needs then look at the free options (AVG, AVAST, AVIRA etc) but before going for it, visit their forums, read newest 3 pages to identify issues. AVAST is a prime example. AVG has issues reported but those are additional components mainly not present in free version.
to counter the argument of A or B AV is better than Windows Defender: detection rate is not 100% secure. Nothing is, same as Real Life, one always has to adapt.
Is WD inferior in terms of signatures to the rest? Perhaps but that is because people do not use it often and don't report infections ( I always reported to ESET, COMODO and even Windows). Does it have all bells and whistles? Nope it doesn't. Is it user friendly? Yes.
Is it light? Yes
To put into prespective, give 3 systems to the same user who's habits are to visit unsecure, infected, spamfest, malware fest sites, click yes on anything in terms of downloads/website pop ups (not to be confused by AV solution popups) type of user:
System with AVG (default settings)
System with AVAST (default settings)
System with WD + WFW + Smartscreen + UAC (basically windows default settings out of box)
1 month later go see which one protected most. You will be surprised. Do that test yourself. Ive done mine and people who knew me from before will know the answer.
Just my 2 cents and experience. Feel free to disagree. And no, this aint to discredit others while giving credit blindly to Microsoft.
Attack the point, not the person.
