I've also found them all to be pretty much the same. Running free Avast and maybe AVG on another machine and virus free since forever. Don't think it really matters much which one you pick, even if it is just windows defender. I run the occasional manual scan with Malwarebytes.
I use BitDefender Free along with occasional scans with Malwarebytes.
For some reason Windows Defender slows file extraction down quite a lot, which is evident when unzipping large files. It's quite possibly something to do with the real-time protection as if I disable that it seems to speed up.
BitDefender seems a bit easier on resources and made my system snappier than it was with Defender.
I think all the well-known AV's are much of a muchness these days and seem to do a pretty decent job if you aren't asking for too much (especially with the free variants)
I’ve been using F-Secure for about 5 years but recently picked up Trojans and believe that BitComet is the culprit. Installed Malware Bytes (expires Saturday) and the scans report 91 events every time it scans. Screen pop ups are really peeing me off.
Norton's Anti-Virus or AVG combined with MalwareBytes and a "Dr.Web's Cure It" scan now and then. Norton's or AVG will do real time scanning and MalwareBytes + Dr. Web's manual scans every second week or even once a month. CCleaner can be used now and then to clean the Computer a bit.
Ive used Kaspersky for a while, its done its job. Most of them will do the job if setup properly and you dont go out of your way to get infected or do dodgy stuff
I like some of the additional Kaspersky features and its detection rate is pretty good.
In the end you probably couldnt go wrong with the big names