To be brutally honest; Chrome.
Yes, I said it. Chrome is worse than IE. For a start, it's slow as hell compared to FF, it feels zoomed out and you can't zoom in or out with the trackpad. It's also clunky when it comes to scrolling with the trackpad. Scrolling with the trackpad is easy on FF, but pretty much harder on Chrome due to how unresponsive it is. I don't understand where all the praise comes from; it's slow, a bit clunky, and doesn't remember passwords as much as other browsers. I'm gonna sound like a hipster in saying this; but Chrome is annoyingly overrated.