Firefox. I switched on all of my machines, MacOS and Windows, a few years ago and rarely have any issues. I was expecting it to be a rough ride based on what I hear around the internet but it was quite the opposite: seamless.

As with most things you'll hear comments on HN with both sides liking and hating it but I never experience the terribleness that comes from those that say it sucks. I also don't mind switching to Chrome when I absolutely have to.

edit: I also use FF on Android and I will admit it has a few more issues than it has on my PC, but nothing that is bad enough to make me use Chrome.