I used to run Kaspersky, then it turned out they had ties to Russian Mafia! So I went with MSE. After a while I got nervous and I did a free Norton trial. It worked fine, the problems reported in the past seem to have been fixed. But I declined to buy it. Went back to MSE, then got nervous again and went with Bitdefender Free. That's what I'm running now. Minimal interference; really the only issue is, I need to let it log in before opening anything up. Then all is well, it's totally non-intrusive.
I agree that it's risky not to run AV. My advice is to use a highly-rated free AV and see how it goes. To think that viruses are a thing of the past, or created by AV companies, is to live dangerously. Of course there are viruses. A day doesn't go by that we don't read of some new hacking plot. There are people out there who want to hurt you. Protect yourself, or you may pay big time.