I got nailed with a really nasty virus attack last December -- I had a good anti-virus program running, but only modest protection beyond that. I ran an anti-spyware scan which apparently triggered the dormant virus prematurely, so I was at the screen when it went active. It was remarkably effective. Took me more than a month to get rid of all traces and get the computer back to where I trusted it again.
Anyway, I've redefined my assessment of "browser performance." I now run ad blockers, script blockers, a cookie "white list," an extensive "Hosts" file, etc. All this has slowed my browser down a bit, but I'm perfectly okay with that!
I still run Windows, but only because I have one program in particular that I really need to run ... and it only has a Windows version. I've told the developers that they could add a Linux version anytime they wanted and it would be okay with me!